001-快速搭建Spring web应用【springboot 2.0.4】-gradle、springboot的启动过程分析、gradle多模块构建

一、概述

　　学习《精通Spring MVC4》书籍笔记

二、笔记

1、快速构建Spring starter web项目几种方式

　　1》使用Spring Tool Suite生成Starter代码；sts是集成的eclipse工具，下载地址：https://spring.io/tools3/sts/all

　　2》使用 idea 14版本以上

　　3》使用站点：https://start.spring.io/ 配置后下载zip文件

　　4》使用https://start.spring.io/站点的curl命令

2、其他 gradle或maven，spring 4 ，java8 lambda，heroku，git

　　git：需要安装，git交互式教程：http://try.github.io/；git交互学习界面：https://learngitbranching.js.org/

　　gradle构建：Gradle是一个基于Apache Ant和Apache Maven概念的项目自动化构建开源工具。它使用一种基于Groovy的特定领域语言(DSL)来声明项目设置，抛弃了基于XML的各种繁琐配置。

　　　　mac上使用：参看官网即可：https://gradle.org/

　　　　　　1、安装java，检测java：javas -version

　　　　　　2、支持手动安装和包安装(推荐)，手动的参看官网

　　　　　　　　brew install gradle

　　　　　　　　注：brew是一个软件包管理工具,类似于centos下的yum或者ubuntu下的apt-get,非常方便,免去了自己手动编译安装的不便

　　　　　　　　　　安装brew：/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

　　　　　　　　　　查看版本：gradle -v；配置idea路径：/usr/local/Cellar/gradle/5.1/libexec 

　　　　　　3、可以基于上面的第4创建一个springboot项目，尝试使用gradle

　　gradle的dependencies

Configuration name	Role	Consumable?	Resolvable?	Description
api	Declaring API dependencies	no	no	This is where you should declare dependencies which are transitively exported to consumers, for compile.
implementation	Declaring implementation dependencies	no	no	This is where you should declare dependencies which are purely internal and not meant to be exposed to consumers. 在这里，您应该声明纯粹内部的依赖关系，而不是要向消费者公开。
compileOnly	Declaring compile only dependencies	yes	yes	This is where you should declare dependencies which are only required at compile time, but should not leak into the runtime. This typically includes dependencies which are shaded when found at runtime. 这是您应该声明仅在编译时需要的依赖项，但不应泄漏到运行时。这通常包括在运行时找到时被着色的依赖项。
runtimeOnly	Declaring runtime dependencies	no	no	This is where you should declare dependencies which are only required at runtime, and not at compile time.
testImplementation	Test dependencies	no	no	This is where you should declare dependencies which are used to compile tests.
testCompileOnly	Declaring test compile only dependencies	yes	yes	This is where you should declare dependencies which are only required at test compile time, but should not leak into the runtime. This typically includes dependencies which are shaded when found at runtime.
testRuntimeOnly	Declaring test runtime dependencies	no	no	This is where you should declare dependencies which are only required at test runtime, and not at test compile time.

参看地址：https://docs.gradle.org/current/userguide/java_library_plugin.html#sec:java_library_separation

3、spring boot

3.1、spring mvc初始步骤

1》初始化Spring MVC的DIspatchServlet；

2》搭建转码过滤器，保证客户端请求进行正确地转码；

3》搭建视图解析器（View resolver），告诉Spring去哪里查找视图，以及他们是使用哪种前端模板编写的（jsp、thymeleaf、freemarker模板等）

4》配置静态资源的位置（css,js）;

5》配置所支持的地域以及资源bundle；

6》配置multipart解析器，保证文件上传能够正常工作；

7》将tomcat或jetty包含进来，从而能够在we服务器上运行我们的应用

8》建立错误页面

spring boot主要是基于约定，默认会在项目中使用上述约定。

3.2、分发器和multipart配置  

在application.properties中添加：

debug=true

查看在springboot启动时候究竟发生了什么

============================
CONDITIONS EVALUATION REPORT
============================


Positive matches:
-----------------

   CodecsAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.http.codec.CodecConfigurer'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   CodecsAutoConfiguration.JacksonCodecConfiguration matched:
      - @ConditionalOnClass found required class 'com.fasterxml.jackson.databind.ObjectMapper'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   CodecsAutoConfiguration.JacksonCodecConfiguration#jacksonCodecCustomizer matched:
      - @ConditionalOnBean (types: com.fasterxml.jackson.databind.ObjectMapper; SearchStrategy: all) found bean 'jacksonObjectMapper' (OnBeanCondition)

   DispatcherServletAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.web.servlet.DispatcherServlet'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)

   DispatcherServletAutoConfiguration.DispatcherServletConfiguration matched:
      - @ConditionalOnClass found required class 'javax.servlet.ServletRegistration'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - Default DispatcherServlet did not find dispatcher servlet beans (DispatcherServletAutoConfiguration.DefaultDispatcherServletCondition)

   DispatcherServletAutoConfiguration.DispatcherServletRegistrationConfiguration matched:
      - @ConditionalOnClass found required class 'javax.servlet.ServletRegistration'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - DispatcherServlet Registration did not find servlet registration bean (DispatcherServletAutoConfiguration.DispatcherServletRegistrationCondition)

   DispatcherServletAutoConfiguration.DispatcherServletRegistrationConfiguration#dispatcherServletRegistration matched:
      - @ConditionalOnBean (names: dispatcherServlet; types: org.springframework.web.servlet.DispatcherServlet; SearchStrategy: all) found bean 'dispatcherServlet' (OnBeanCondition)

   EmbeddedWebServerFactoryCustomizerAutoConfiguration.TomcatWebServerFactoryCustomizerConfiguration matched:
      - @ConditionalOnClass found required classes 'org.apache.catalina.startup.Tomcat', 'org.apache.coyote.UpgradeProtocol'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   ErrorMvcAutoConfiguration matched:
      - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'org.springframework.web.servlet.DispatcherServlet'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)

   ErrorMvcAutoConfiguration#basicErrorController matched:
      - @ConditionalOnMissingBean (types: org.springframework.boot.web.servlet.error.ErrorController; SearchStrategy: current) did not find any beans (OnBeanCondition)

   ErrorMvcAutoConfiguration#errorAttributes matched:
      - @ConditionalOnMissingBean (types: org.springframework.boot.web.servlet.error.ErrorAttributes; SearchStrategy: current) did not find any beans (OnBeanCondition)

   ErrorMvcAutoConfiguration.DefaultErrorViewResolverConfiguration#conventionErrorViewResolver matched:
      - @ConditionalOnBean (types: org.springframework.web.servlet.DispatcherServlet; SearchStrategy: all) found bean 'dispatcherServlet'; @ConditionalOnMissingBean (types: org.springframework.boot.autoconfigure.web.servlet.error.DefaultErrorViewResolver; SearchStrategy: all) did not find any beans (OnBeanCondition)

   ErrorMvcAutoConfiguration.WhitelabelErrorViewConfiguration matched:
      - @ConditionalOnProperty (server.error.whitelabel.enabled) matched (OnPropertyCondition)
      - ErrorTemplate Missing did not find error template view (ErrorMvcAutoConfiguration.ErrorTemplateMissingCondition)

   ErrorMvcAutoConfiguration.WhitelabelErrorViewConfiguration#beanNameViewResolver matched:
      - @ConditionalOnMissingBean (types: org.springframework.web.servlet.view.BeanNameViewResolver; SearchStrategy: all) did not find any beans (OnBeanCondition)

   ErrorMvcAutoConfiguration.WhitelabelErrorViewConfiguration#defaultErrorView matched:
      - @ConditionalOnMissingBean (names: error; SearchStrategy: all) did not find any beans (OnBeanCondition)

   GenericCacheConfiguration matched:
      - Cache org.springframework.boot.autoconfigure.cache.GenericCacheConfiguration automatic cache type (CacheCondition)

   HttpEncodingAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.web.filter.CharacterEncodingFilter'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)
      - @ConditionalOnProperty (spring.http.encoding.enabled) matched (OnPropertyCondition)

   HttpEncodingAutoConfiguration#characterEncodingFilter matched:
      - @ConditionalOnMissingBean (types: org.springframework.web.filter.CharacterEncodingFilter; SearchStrategy: all) did not find any beans (OnBeanCondition)

   HttpMessageConvertersAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.http.converter.HttpMessageConverter'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   HttpMessageConvertersAutoConfiguration#messageConverters matched:
      - @ConditionalOnMissingBean (types: org.springframework.boot.autoconfigure.http.HttpMessageConverters; SearchStrategy: all) did not find any beans (OnBeanCondition)

   HttpMessageConvertersAutoConfiguration.StringHttpMessageConverterConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.http.converter.StringHttpMessageConverter'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   HttpMessageConvertersAutoConfiguration.StringHttpMessageConverterConfiguration#stringHttpMessageConverter matched:
      - @ConditionalOnMissingBean (types: org.springframework.http.converter.StringHttpMessageConverter; SearchStrategy: all) did not find any beans (OnBeanCondition)

   JacksonAutoConfiguration matched:
      - @ConditionalOnClass found required class 'com.fasterxml.jackson.databind.ObjectMapper'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   JacksonAutoConfiguration.Jackson2ObjectMapperBuilderCustomizerConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.http.converter.json.Jackson2ObjectMapperBuilder'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   JacksonAutoConfiguration.JacksonObjectMapperBuilderConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.http.converter.json.Jackson2ObjectMapperBuilder'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   JacksonAutoConfiguration.JacksonObjectMapperBuilderConfiguration#jacksonObjectMapperBuilder matched:
      - @ConditionalOnMissingBean (types: org.springframework.http.converter.json.Jackson2ObjectMapperBuilder; SearchStrategy: all) did not find any beans (OnBeanCondition)

   JacksonAutoConfiguration.JacksonObjectMapperConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.http.converter.json.Jackson2ObjectMapperBuilder'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   JacksonAutoConfiguration.JacksonObjectMapperConfiguration#jacksonObjectMapper matched:
      - @ConditionalOnMissingBean (types: com.fasterxml.jackson.databind.ObjectMapper; SearchStrategy: all) did not find any beans (OnBeanCondition)

   JacksonAutoConfiguration.ParameterNamesModuleConfiguration matched:
      - @ConditionalOnClass found required class 'com.fasterxml.jackson.module.paramnames.ParameterNamesModule'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   JacksonAutoConfiguration.ParameterNamesModuleConfiguration#parameterNamesModule matched:
      - @ConditionalOnMissingBean (types: com.fasterxml.jackson.module.paramnames.ParameterNamesModule; SearchStrategy: all) did not find any beans (OnBeanCondition)

   JacksonHttpMessageConvertersConfiguration.MappingJackson2HttpMessageConverterConfiguration matched:
      - @ConditionalOnClass found required class 'com.fasterxml.jackson.databind.ObjectMapper'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - @ConditionalOnProperty (spring.http.converters.preferred-json-mapper=jackson) matched (OnPropertyCondition)
      - @ConditionalOnBean (types: com.fasterxml.jackson.databind.ObjectMapper; SearchStrategy: all) found bean 'jacksonObjectMapper' (OnBeanCondition)

   JacksonHttpMessageConvertersConfiguration.MappingJackson2HttpMessageConverterConfiguration#mappingJackson2HttpMessageConverter matched:
      - @ConditionalOnMissingBean (types: org.springframework.http.converter.json.MappingJackson2HttpMessageConverter; SearchStrategy: all) did not find any beans (OnBeanCondition)

   JmxAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.jmx.export.MBeanExporter'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - @ConditionalOnProperty (spring.jmx.enabled=true) matched (OnPropertyCondition)

   JmxAutoConfiguration#mbeanExporter matched:
      - @ConditionalOnMissingBean (types: org.springframework.jmx.export.MBeanExporter; SearchStrategy: current) did not find any beans (OnBeanCondition)

   JmxAutoConfiguration#mbeanServer matched:
      - @ConditionalOnMissingBean (types: javax.management.MBeanServer; SearchStrategy: all) did not find any beans (OnBeanCondition)

   JmxAutoConfiguration#objectNamingStrategy matched:
      - @ConditionalOnMissingBean (types: org.springframework.jmx.export.naming.ObjectNamingStrategy; SearchStrategy: current) did not find any beans (OnBeanCondition)

   MultipartAutoConfiguration matched:
      - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'org.springframework.web.multipart.support.StandardServletMultipartResolver', 'javax.servlet.MultipartConfigElement'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)
      - @ConditionalOnProperty (spring.servlet.multipart.enabled) matched (OnPropertyCondition)

   MultipartAutoConfiguration#multipartConfigElement matched:
      - @ConditionalOnMissingBean (types: javax.servlet.MultipartConfigElement,org.springframework.web.multipart.commons.CommonsMultipartResolver; SearchStrategy: all) did not find any beans (OnBeanCondition)

   MultipartAutoConfiguration#multipartResolver matched:
      - @ConditionalOnMissingBean (types: org.springframework.web.multipart.MultipartResolver; SearchStrategy: all) did not find any beans (OnBeanCondition)

   NoOpCacheConfiguration matched:
      - Cache org.springframework.boot.autoconfigure.cache.NoOpCacheConfiguration automatic cache type (CacheCondition)

   PropertyPlaceholderAutoConfiguration#propertySourcesPlaceholderConfigurer matched:
      - @ConditionalOnMissingBean (types: org.springframework.context.support.PropertySourcesPlaceholderConfigurer; SearchStrategy: current) did not find any beans (OnBeanCondition)

   RestTemplateAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.web.client.RestTemplate'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   RestTemplateAutoConfiguration#restTemplateBuilder matched:
      - @ConditionalOnMissingBean (types: org.springframework.boot.web.client.RestTemplateBuilder; SearchStrategy: all) did not find any beans (OnBeanCondition)

   ServletWebServerFactoryAutoConfiguration matched:
      - @ConditionalOnClass found required class 'javax.servlet.ServletRequest'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)

   ServletWebServerFactoryAutoConfiguration#tomcatServletWebServerFactoryCustomizer matched:
      - @ConditionalOnClass found required class 'org.apache.catalina.startup.Tomcat'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   ServletWebServerFactoryConfiguration.EmbeddedTomcat matched:
      - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'org.apache.catalina.startup.Tomcat', 'org.apache.coyote.UpgradeProtocol'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - @ConditionalOnMissingBean (types: org.springframework.boot.web.servlet.server.ServletWebServerFactory; SearchStrategy: current) did not find any beans (OnBeanCondition)

   SimpleCacheConfiguration matched:
      - Cache org.springframework.boot.autoconfigure.cache.SimpleCacheConfiguration automatic cache type (CacheCondition)

   SpringApplicationAdminJmxAutoConfiguration matched:
      - @ConditionalOnProperty (spring.application.admin.enabled=true) matched (OnPropertyCondition)

   SpringApplicationAdminJmxAutoConfiguration#springApplicationAdminRegistrar matched:
      - @ConditionalOnMissingBean (types: org.springframework.boot.admin.SpringApplicationAdminMXBeanRegistrar; SearchStrategy: all) did not find any beans (OnBeanCondition)

   ValidationAutoConfiguration matched:
      - @ConditionalOnClass found required class 'javax.validation.executable.ExecutableValidator'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - @ConditionalOnResource found location classpath:META-INF/services/javax.validation.spi.ValidationProvider (OnResourceCondition)

   ValidationAutoConfiguration#defaultValidator matched:
      - @ConditionalOnMissingBean (types: javax.validation.Validator; SearchStrategy: all) did not find any beans (OnBeanCondition)

   ValidationAutoConfiguration#methodValidationPostProcessor matched:
      - @ConditionalOnMissingBean (types: org.springframework.validation.beanvalidation.MethodValidationPostProcessor; SearchStrategy: all) did not find any beans (OnBeanCondition)

   WebMvcAutoConfiguration matched:
      - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'org.springframework.web.servlet.DispatcherServlet', 'org.springframework.web.servlet.config.annotation.WebMvcConfigurer'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)
      - @ConditionalOnMissingBean (types: org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; SearchStrategy: all) did not find any beans (OnBeanCondition)

   WebMvcAutoConfiguration#hiddenHttpMethodFilter matched:
      - @ConditionalOnMissingBean (types: org.springframework.web.filter.HiddenHttpMethodFilter; SearchStrategy: all) did not find any beans (OnBeanCondition)

   WebMvcAutoConfiguration#httpPutFormContentFilter matched:
      - @ConditionalOnProperty (spring.mvc.formcontent.putfilter.enabled) matched (OnPropertyCondition)
      - @ConditionalOnMissingBean (types: org.springframework.web.filter.HttpPutFormContentFilter; SearchStrategy: all) did not find any beans (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#defaultViewResolver matched:
      - @ConditionalOnMissingBean (types: org.springframework.web.servlet.view.InternalResourceViewResolver; SearchStrategy: all) did not find any beans (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#requestContextFilter matched:
      - @ConditionalOnMissingBean (types: org.springframework.web.context.request.RequestContextListener,org.springframework.web.filter.RequestContextFilter; SearchStrategy: all) did not find any beans (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#viewResolver matched:
      - @ConditionalOnBean (types: org.springframework.web.servlet.ViewResolver; SearchStrategy: all) found beans 'defaultViewResolver', 'beanNameViewResolver', 'mvcViewResolver'; @ConditionalOnMissingBean (names: viewResolver; types: org.springframework.web.servlet.view.ContentNegotiatingViewResolver; SearchStrategy: all) did not find any beans (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter.FaviconConfiguration matched:
      - @ConditionalOnProperty (spring.mvc.favicon.enabled) matched (OnPropertyCondition)

   WebSocketServletAutoConfiguration matched:
      - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'javax.websocket.server.ServerContainer'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
      - found ConfigurableWebEnvironment (OnWebApplicationCondition)

   WebSocketServletAutoConfiguration.TomcatWebSocketConfiguration matched:
      - @ConditionalOnClass found required classes 'org.apache.catalina.startup.Tomcat', 'org.apache.tomcat.websocket.server.WsSci'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   WebSocketServletAutoConfiguration.TomcatWebSocketConfiguration#websocketContainerCustomizer matched:
      - @ConditionalOnMissingBean (names: websocketServletWebServerCustomizer; SearchStrategy: all) did not find any beans (OnBeanCondition)


Negative matches:
-----------------

   ActiveMQAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'javax.jms.ConnectionFactory', 'org.apache.activemq.ActiveMQConnectionFactory' (OnClassCondition)

   AopAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.aspectj.lang.annotation.Aspect', 'org.aspectj.lang.reflect.Advice', 'org.aspectj.weaver.AnnotatedElement' (OnClassCondition)

   ArtemisAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'javax.jms.ConnectionFactory', 'org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory' (OnClassCondition)

   BatchAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.batch.core.launch.JobLauncher', 'org.springframework.jdbc.core.JdbcOperations' (OnClassCondition)

   CacheAutoConfiguration:
      Did not match:
         - @ConditionalOnBean (types: org.springframework.cache.interceptor.CacheAspectSupport; SearchStrategy: all) did not find any beans of type org.springframework.cache.interceptor.CacheAspectSupport (OnBeanCondition)
      Matched:
         - @ConditionalOnClass found required class 'org.springframework.cache.CacheManager'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   CacheAutoConfiguration.CacheManagerJpaDependencyConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean' (OnClassCondition)
         - Ancestor org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration did not match (ConditionEvaluationReport.AncestorsMatchedCondition)

   CaffeineCacheConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.github.benmanes.caffeine.cache.Caffeine', 'org.springframework.cache.caffeine.CaffeineCacheManager' (OnClassCondition)

   CassandraAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.datastax.driver.core.Cluster' (OnClassCondition)

   CassandraDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.datastax.driver.core.Cluster', 'org.springframework.data.cassandra.core.CassandraAdminOperations' (OnClassCondition)

   CassandraReactiveDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.datastax.driver.core.Cluster', 'org.springframework.data.cassandra.core.ReactiveCassandraTemplate', 'reactor.core.publisher.Flux' (OnClassCondition)

   CassandraReactiveRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.data.cassandra.ReactiveSession', 'org.springframework.data.cassandra.repository.ReactiveCassandraRepository' (OnClassCondition)

   CassandraRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.datastax.driver.core.Session', 'org.springframework.data.cassandra.repository.CassandraRepository' (OnClassCondition)

   CloudAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.cloud.config.java.CloudScanConfiguration' (OnClassCondition)

   CouchbaseAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.couchbase.client.java.CouchbaseBucket', 'com.couchbase.client.java.Cluster' (OnClassCondition)

   CouchbaseCacheConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.couchbase.client.java.Bucket', 'com.couchbase.client.spring.cache.CouchbaseCacheManager' (OnClassCondition)

   CouchbaseDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.couchbase.client.java.Bucket', 'org.springframework.data.couchbase.repository.CouchbaseRepository' (OnClassCondition)

   CouchbaseReactiveDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.couchbase.client.java.Bucket', 'org.springframework.data.couchbase.repository.ReactiveCouchbaseRepository', 'reactor.core.publisher.Flux' (OnClassCondition)

   CouchbaseReactiveRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.couchbase.client.java.Bucket', 'org.springframework.data.couchbase.repository.ReactiveCouchbaseRepository', 'reactor.core.publisher.Flux' (OnClassCondition)

   CouchbaseRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.couchbase.client.java.Bucket', 'org.springframework.data.couchbase.repository.CouchbaseRepository' (OnClassCondition)

   DataSourceAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType' (OnClassCondition)

   DataSourceTransactionManagerAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.jdbc.core.JdbcTemplate', 'org.springframework.transaction.PlatformTransactionManager' (OnClassCondition)

   DispatcherServletAutoConfiguration.DispatcherServletConfiguration#multipartResolver:
      Did not match:
         - @ConditionalOnBean (types: org.springframework.web.multipart.MultipartResolver; SearchStrategy: all) did not find any beans of type org.springframework.web.multipart.MultipartResolver (OnBeanCondition)

   EhCacheCacheConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'net.sf.ehcache.Cache', 'org.springframework.cache.ehcache.EhCacheCacheManager' (OnClassCondition)

   ElasticsearchAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.elasticsearch.client.Client', 'org.springframework.data.elasticsearch.client.TransportClientFactoryBean' (OnClassCondition)

   ElasticsearchDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.elasticsearch.client.Client', 'org.springframework.data.elasticsearch.core.ElasticsearchTemplate' (OnClassCondition)

   ElasticsearchRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.elasticsearch.client.Client', 'org.springframework.data.elasticsearch.repository.ElasticsearchRepository' (OnClassCondition)

   EmbeddedLdapAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.unboundid.ldap.listener.InMemoryDirectoryServer' (OnClassCondition)

   EmbeddedMongoAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.mongodb.MongoClient', 'de.flapdoodle.embed.mongo.MongodStarter' (OnClassCondition)

   EmbeddedWebServerFactoryCustomizerAutoConfiguration.JettyWebServerFactoryCustomizerConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.eclipse.jetty.server.Server', 'org.eclipse.jetty.util.Loader', 'org.eclipse.jetty.webapp.WebAppContext' (OnClassCondition)

   EmbeddedWebServerFactoryCustomizerAutoConfiguration.UndertowWebServerFactoryCustomizerConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'io.undertow.Undertow', 'org.xnio.SslClientAuthMode' (OnClassCondition)

   ErrorWebFluxAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.web.reactive.config.WebFluxConfigurer' (OnClassCondition)

   FlywayAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.flywaydb.core.Flyway' (OnClassCondition)

   FreeMarkerAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'freemarker.template.Configuration', 'org.springframework.ui.freemarker.FreeMarkerConfigurationFactory' (OnClassCondition)

   GroovyTemplateAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'groovy.text.markup.MarkupTemplateEngine' (OnClassCondition)

   GsonAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.google.gson.Gson' (OnClassCondition)

   GsonHttpMessageConvertersConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.google.gson.Gson' (OnClassCondition)

   H2ConsoleAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.h2.server.web.WebServlet' (OnClassCondition)

   HazelcastAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.hazelcast.core.HazelcastInstance' (OnClassCondition)

   HazelcastCacheConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.hazelcast.core.HazelcastInstance', 'com.hazelcast.spring.cache.HazelcastCacheManager' (OnClassCondition)

   HazelcastJpaDependencyAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.hazelcast.core.HazelcastInstance', 'org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean' (OnClassCondition)

   HibernateJpaAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean', 'javax.persistence.EntityManager' (OnClassCondition)

   HttpHandlerAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.web.reactive.DispatcherHandler' (OnClassCondition)

   HypermediaAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.hateoas.Resource', 'org.springframework.plugin.core.Plugin' (OnClassCondition)

   InfinispanCacheConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.infinispan.spring.provider.SpringEmbeddedCacheManager' (OnClassCondition)

   InfluxDbAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.influxdb.InfluxDB' (OnClassCondition)

   IntegrationAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.integration.config.EnableIntegration' (OnClassCondition)

   JCacheCacheConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'javax.cache.Caching', 'org.springframework.cache.jcache.JCacheCacheManager' (OnClassCondition)

   JacksonAutoConfiguration.JodaDateTimeJacksonConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.joda.time.DateTime', 'com.fasterxml.jackson.datatype.joda.ser.DateTimeSerializer', 'com.fasterxml.jackson.datatype.joda.cfg.JacksonJodaDateFormat' (OnClassCondition)

   JacksonHttpMessageConvertersConfiguration.MappingJackson2XmlHttpMessageConverterConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.fasterxml.jackson.dataformat.xml.XmlMapper' (OnClassCondition)

   JdbcTemplateAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.jdbc.core.JdbcTemplate' (OnClassCondition)

   JerseyAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.glassfish.jersey.server.spring.SpringComponentProvider' (OnClassCondition)

   JestAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'io.searchbox.client.JestClient' (OnClassCondition)

   JmsAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'javax.jms.Message', 'org.springframework.jms.core.JmsTemplate' (OnClassCondition)

   JndiConnectionFactoryAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.jms.core.JmsTemplate' (OnClassCondition)

   JndiDataSourceAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType' (OnClassCondition)

   JooqAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.jooq.DSLContext' (OnClassCondition)

   JpaRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.jpa.repository.JpaRepository' (OnClassCondition)

   JsonbAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'javax.json.bind.Jsonb' (OnClassCondition)

   JsonbHttpMessageConvertersConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'javax.json.bind.Jsonb' (OnClassCondition)

   JtaAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'javax.transaction.Transaction' (OnClassCondition)

   KafkaAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.kafka.core.KafkaTemplate' (OnClassCondition)

   LdapAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.ldap.core.ContextSource' (OnClassCondition)

   LdapDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.ldap.repository.LdapRepository' (OnClassCondition)

   LdapRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.ldap.repository.LdapRepository' (OnClassCondition)

   LiquibaseAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'liquibase.integration.spring.SpringLiquibase', 'liquibase.change.DatabaseChange' (OnClassCondition)

   MailSenderAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'javax.mail.internet.MimeMessage', 'org.springframework.mail.MailSender' (OnClassCondition)

   MailSenderValidatorAutoConfiguration:
      Did not match:
         - @ConditionalOnProperty (spring.mail.test-connection) did not find property 'test-connection' (OnPropertyCondition)

   MessageSourceAutoConfiguration:
      Did not match:
         - ResourceBundle did not find bundle with basename messages (MessageSourceAutoConfiguration.ResourceBundleCondition)

   MongoAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.mongodb.MongoClient' (OnClassCondition)

   MongoDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.mongodb.MongoClient', 'org.springframework.data.mongodb.core.MongoTemplate' (OnClassCondition)

   MongoReactiveAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.mongodb.reactivestreams.client.MongoClient' (OnClassCondition)

   MongoReactiveDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.mongodb.reactivestreams.client.MongoClient', 'org.springframework.data.mongodb.core.ReactiveMongoTemplate' (OnClassCondition)

   MongoReactiveRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.mongodb.reactivestreams.client.MongoClient', 'org.springframework.data.mongodb.repository.ReactiveMongoRepository' (OnClassCondition)

   MongoRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'com.mongodb.MongoClient', 'org.springframework.data.mongodb.repository.MongoRepository' (OnClassCondition)

   MustacheAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.samskivert.mustache.Mustache' (OnClassCondition)

   Neo4jDataAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.neo4j.ogm.session.SessionFactory', 'org.springframework.data.neo4j.transaction.Neo4jTransactionManager', 'org.springframework.transaction.PlatformTransactionManager' (OnClassCondition)

   Neo4jRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.neo4j.ogm.session.Neo4jSession', 'org.springframework.data.neo4j.repository.Neo4jRepository' (OnClassCondition)

   OAuth2ClientAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.security.config.annotation.web.configuration.EnableWebSecurity', 'org.springframework.security.oauth2.client.registration.ClientRegistration' (OnClassCondition)

   PersistenceExceptionTranslationAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor' (OnClassCondition)

   ProjectInfoAutoConfiguration#buildProperties:
      Did not match:
         - @ConditionalOnResource did not find resource '${spring.info.build.location:classpath:META-INF/build-info.properties}' (OnResourceCondition)

   ProjectInfoAutoConfiguration#gitProperties:
      Did not match:
         - GitResource did not find git info at classpath:git.properties (ProjectInfoAutoConfiguration.GitResourceAvailableCondition)

   QuartzAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.quartz.Scheduler', 'org.springframework.scheduling.quartz.SchedulerFactoryBean', 'org.springframework.transaction.PlatformTransactionManager' (OnClassCondition)

   RabbitAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.amqp.rabbit.core.RabbitTemplate', 'com.rabbitmq.client.Channel' (OnClassCondition)

   ReactiveUserDetailsServiceAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.security.authentication.ReactiveAuthenticationManager' (OnClassCondition)

   ReactiveWebServerFactoryAutoConfiguration:
      Did not match:
         - not a reactive web application (OnWebApplicationCondition)
      Matched:
         - @ConditionalOnClass found required class 'org.springframework.http.ReactiveHttpInputMessage'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   ReactorCoreAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'reactor.core.publisher.Mono', 'reactor.core.publisher.Flux' (OnClassCondition)

   RedisAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.redis.core.RedisOperations' (OnClassCondition)

   RedisCacheConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.redis.connection.RedisConnectionFactory' (OnClassCondition)

   RedisReactiveAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.data.redis.connection.ReactiveRedisConnectionFactory', 'org.springframework.data.redis.core.ReactiveRedisTemplate', 'reactor.core.publisher.Flux' (OnClassCondition)

   RedisRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.redis.repository.configuration.EnableRedisRepositories' (OnClassCondition)

   RepositoryRestMvcAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration' (OnClassCondition)

   SecurityAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.security.authentication.DefaultAuthenticationEventPublisher' (OnClassCondition)

   SecurityFilterAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.security.web.context.AbstractSecurityWebApplicationInitializer', 'org.springframework.security.config.http.SessionCreationPolicy' (OnClassCondition)

   SendGridAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'com.sendgrid.SendGrid' (OnClassCondition)

   ServletWebServerFactoryConfiguration.EmbeddedJetty:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.eclipse.jetty.server.Server', 'org.eclipse.jetty.util.Loader', 'org.eclipse.jetty.webapp.WebAppContext' (OnClassCondition)

   ServletWebServerFactoryConfiguration.EmbeddedUndertow:
      Did not match:
         - @ConditionalOnClass did not find required classes 'io.undertow.Undertow', 'org.xnio.SslClientAuthMode' (OnClassCondition)

   SessionAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.session.Session' (OnClassCondition)

   SolrAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.apache.solr.client.solrj.impl.HttpSolrClient', 'org.apache.solr.client.solrj.impl.CloudSolrClient' (OnClassCondition)

   SolrRepositoriesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.apache.solr.client.solrj.SolrClient', 'org.springframework.data.solr.repository.SolrRepository' (OnClassCondition)

   SpringDataWebAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.data.web.PageableHandlerMethodArgumentResolver' (OnClassCondition)

   ThymeleafAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.thymeleaf.templatemode.TemplateMode' (OnClassCondition)

   TransactionAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.transaction.PlatformTransactionManager' (OnClassCondition)

   UserDetailsServiceAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.security.authentication.AuthenticationManager' (OnClassCondition)

   WebClientAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.web.reactive.function.client.WebClient' (OnClassCondition)

   WebFluxAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.web.reactive.config.WebFluxConfigurer' (OnClassCondition)

   WebFluxSecurityConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity', 'org.springframework.security.web.server.WebFilterChainProxy' (OnClassCondition)

   WebMvcAutoConfiguration.ResourceChainCustomizerConfiguration:
      Did not match:
         - @ConditionalOnEnabledResourceChain did not find class org.webjars.WebJarAssetLocator (OnEnabledResourceChainCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#beanNameViewResolver:
      Did not match:
         - @ConditionalOnMissingBean (types: org.springframework.web.servlet.view.BeanNameViewResolver; SearchStrategy: all) found beans of type 'org.springframework.web.servlet.view.BeanNameViewResolver' beanNameViewResolver (OnBeanCondition)

   WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter#localeResolver:
      Did not match:
         - @ConditionalOnProperty (spring.mvc.locale) did not find property 'locale' (OnPropertyCondition)

   WebServicesAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.ws.transport.http.MessageDispatcherServlet' (OnClassCondition)

   WebSocketMessagingAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer' (OnClassCondition)

   WebSocketReactiveAutoConfiguration:
      Did not match:
         - not a reactive web application (OnWebApplicationCondition)
      Matched:
         - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'javax.websocket.server.ServerContainer'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

   WebSocketServletAutoConfiguration.JettyWebSocketConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'org.eclipse.jetty.websocket.jsr356.server.deploy.WebSocketServerContainerInitializer' (OnClassCondition)

   WebSocketServletAutoConfiguration.UndertowWebSocketConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required class 'io.undertow.websockets.jsr.Bootstrap' (OnClassCondition)

   XADataSourceAutoConfiguration:
      Did not match:
         - @ConditionalOnClass did not find required classes 'javax.transaction.TransactionManager', 'org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType' (OnClassCondition)


Exclusions:
-----------

    None


Unconditional classes:
----------------------

    org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration

    org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration

    org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration

    org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration

    org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration

此处便是Spring Boot的自动配置报告。主要分为两部分：1、匹配上的（postivie matches），列出了应用中，所有的自动配置；2、没有匹配的（negative matches）,没有满足的自动匹配。

查看关键的自动配置：

3.2.1、DispatcherServletAutoConfiguration自动配置

源码：

/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.autoconfigure.web.servlet;

import java.util.Arrays;
import java.util.List;

import javax.servlet.MultipartConfigElement;
import javax.servlet.ServletRegistration;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.AutoConfigureOrder;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionMessage;
import org.springframework.boot.autoconfigure.condition.ConditionMessage.Style;
import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.type.AnnotatedTypeMetadata;
import org.springframework.web.multipart.MultipartResolver;
import org.springframework.web.servlet.DispatcherServlet;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for the Spring
 * {@link DispatcherServlet}. Should work for a standalone application where an embedded
 * web server is already present and also for a deployable application using
 * {@link SpringBootServletInitializer}.
 *
 * @author Phillip Webb
 * @author Dave Syer
 * @author Stephane Nicoll
 * @author Brian Clozel
 */
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@Configuration
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass(DispatcherServlet.class)
@AutoConfigureAfter(ServletWebServerFactoryAutoConfiguration.class)
@EnableConfigurationProperties(ServerProperties.class)
public class DispatcherServletAutoConfiguration {

    /*
     * The bean name for a DispatcherServlet that will be mapped to the root URL "/"
     */
    public static final String DEFAULT_DISPATCHER_SERVLET_BEAN_NAME = "dispatcherServlet";

    /*
     * The bean name for a ServletRegistrationBean for the DispatcherServlet "/"
     */
    public static final String DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME = "dispatcherServletRegistration";

    @Configuration
    @Conditional(DefaultDispatcherServletCondition.class)
    @ConditionalOnClass(ServletRegistration.class)
    @EnableConfigurationProperties(WebMvcProperties.class)
    protected static class DispatcherServletConfiguration {

        private final WebMvcProperties webMvcProperties;

        public DispatcherServletConfiguration(WebMvcProperties webMvcProperties) {
            this.webMvcProperties = webMvcProperties;
        }

        @Bean(name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
        public DispatcherServlet dispatcherServlet() {
            DispatcherServlet dispatcherServlet = new DispatcherServlet();
            dispatcherServlet.setDispatchOptionsRequest(
                    this.webMvcProperties.isDispatchOptionsRequest());
            dispatcherServlet.setDispatchTraceRequest(
                    this.webMvcProperties.isDispatchTraceRequest());
            dispatcherServlet.setThrowExceptionIfNoHandlerFound(
                    this.webMvcProperties.isThrowExceptionIfNoHandlerFound());
            return dispatcherServlet;
        }

        @Bean
        @ConditionalOnBean(MultipartResolver.class)
        @ConditionalOnMissingBean(name = DispatcherServlet.MULTIPART_RESOLVER_BEAN_NAME)
        public MultipartResolver multipartResolver(MultipartResolver resolver) {
            // Detect if the user has created a MultipartResolver but named it incorrectly
            return resolver;
        }

    }

    @Configuration
    @Conditional(DispatcherServletRegistrationCondition.class)
    @ConditionalOnClass(ServletRegistration.class)
    @EnableConfigurationProperties(WebMvcProperties.class)
    @Import(DispatcherServletConfiguration.class)
    protected static class DispatcherServletRegistrationConfiguration {

        private final ServerProperties serverProperties;

        private final WebMvcProperties webMvcProperties;

        private final MultipartConfigElement multipartConfig;

        public DispatcherServletRegistrationConfiguration(
                ServerProperties serverProperties, WebMvcProperties webMvcProperties,
                ObjectProvider<MultipartConfigElement> multipartConfigProvider) {
            this.serverProperties = serverProperties;
            this.webMvcProperties = webMvcProperties;
            this.multipartConfig = multipartConfigProvider.getIfAvailable();
        }

        @Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
        @ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
        public DispatcherServletRegistrationBean dispatcherServletRegistration(
                DispatcherServlet dispatcherServlet) {
            DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(
                    dispatcherServlet, this.serverProperties.getServlet().getPath());
            registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
            registration.setLoadOnStartup(
                    this.webMvcProperties.getServlet().getLoadOnStartup());
            if (this.multipartConfig != null) {
                registration.setMultipartConfig(this.multipartConfig);
            }
            return registration;
        }

    }

    @Order(Ordered.LOWEST_PRECEDENCE - 10)
    private static class DefaultDispatcherServletCondition extends SpringBootCondition {

        @Override
        public ConditionOutcome getMatchOutcome(ConditionContext context,
                AnnotatedTypeMetadata metadata) {
            ConditionMessage.Builder message = ConditionMessage
                    .forCondition("Default DispatcherServlet");
            ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
            List<String> dispatchServletBeans = Arrays.asList(beanFactory
                    .getBeanNamesForType(DispatcherServlet.class, false, false));
            if (dispatchServletBeans.contains(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)) {
                return ConditionOutcome.noMatch(message.found("dispatcher servlet bean")
                        .items(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
            }
            if (beanFactory.containsBean(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)) {
                return ConditionOutcome
                        .noMatch(message.found("non dispatcher servlet bean")
                                .items(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
            }
            if (dispatchServletBeans.isEmpty()) {
                return ConditionOutcome
                        .match(message.didNotFind("dispatcher servlet beans").atAll());
            }
            return ConditionOutcome.match(message
                    .found("dispatcher servlet bean", "dispatcher servlet beans")
                    .items(Style.QUOTE, dispatchServletBeans)
                    .append("and none is named " + DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
        }

    }

    @Order(Ordered.LOWEST_PRECEDENCE - 10)
    private static class DispatcherServletRegistrationCondition
            extends SpringBootCondition {

        @Override
        public ConditionOutcome getMatchOutcome(ConditionContext context,
                AnnotatedTypeMetadata metadata) {
            ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
            ConditionOutcome outcome = checkDefaultDispatcherName(beanFactory);
            if (!outcome.isMatch()) {
                return outcome;
            }
            return checkServletRegistration(beanFactory);
        }

        private ConditionOutcome checkDefaultDispatcherName(
                ConfigurableListableBeanFactory beanFactory) {
            List<String> servlets = Arrays.asList(beanFactory
                    .getBeanNamesForType(DispatcherServlet.class, false, false));
            boolean containsDispatcherBean = beanFactory
                    .containsBean(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
            if (containsDispatcherBean
                    && !servlets.contains(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)) {
                return ConditionOutcome
                        .noMatch(startMessage().found("non dispatcher servlet")
                                .items(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
            }
            return ConditionOutcome.match();
        }

        private ConditionOutcome checkServletRegistration(
                ConfigurableListableBeanFactory beanFactory) {
            ConditionMessage.Builder message = startMessage();
            List<String> registrations = Arrays.asList(beanFactory
                    .getBeanNamesForType(ServletRegistrationBean.class, false, false));
            boolean containsDispatcherRegistrationBean = beanFactory
                    .containsBean(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME);
            if (registrations.isEmpty()) {
                if (containsDispatcherRegistrationBean) {
                    return ConditionOutcome
                            .noMatch(message.found("non servlet registration bean").items(
                                    DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
                }
                return ConditionOutcome
                        .match(message.didNotFind("servlet registration bean").atAll());
            }
            if (registrations
                    .contains(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)) {
                return ConditionOutcome.noMatch(message.found("servlet registration bean")
                        .items(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
            }
            if (containsDispatcherRegistrationBean) {
                return ConditionOutcome
                        .noMatch(message.found("non servlet registration bean").items(
                                DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
            }
            return ConditionOutcome.match(message.found("servlet registration beans")
                    .items(Style.QUOTE, registrations).append("and none is named "
                            + DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
        }

        private ConditionMessage.Builder startMessage() {
            return ConditionMessage.forCondition("DispatcherServlet Registration");
        }

    }

}

是一个典型的Spring boot配置类。

　　使用了@Configuration注解

　　通过@AutoConfigureOrder注解来声明优先等级，需要优先进行配置

可以看到具体的分发器DispatcherSerlvet以及multipart解析器的配置　　

3.3、视图解析器、静态资源以及区域配置

WebMvcAutoConfiguration自动配置

源码

/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.autoconfigure.web.servlet;

import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.Optional;

import javax.servlet.Servlet;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.AutoConfigureOrder;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProviders;
import org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration;
import org.springframework.boot.autoconfigure.validation.ValidatorAdapter;
import org.springframework.boot.autoconfigure.web.ConditionalOnEnabledResourceChain;
import org.springframework.boot.autoconfigure.web.ResourceProperties;
import org.springframework.boot.autoconfigure.web.ResourceProperties.Strategy;
import org.springframework.boot.autoconfigure.web.format.WebConversionService;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.servlet.filter.OrderedHiddenHttpMethodFilter;
import org.springframework.boot.web.servlet.filter.OrderedHttpPutFormContentFilter;
import org.springframework.boot.web.servlet.filter.OrderedRequestContextFilter;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.Primary;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.convert.converter.GenericConverter;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.format.Formatter;
import org.springframework.format.FormatterRegistry;
import org.springframework.format.support.FormattingConversionService;
import org.springframework.http.CacheControl;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.util.ClassUtils;
import org.springframework.validation.DefaultMessageCodesResolver;
import org.springframework.validation.MessageCodesResolver;
import org.springframework.validation.Validator;
import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.accept.ContentNegotiationManager;
import org.springframework.web.accept.ContentNegotiationStrategy;
import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextListener;
import org.springframework.web.filter.HiddenHttpMethodFilter;
import org.springframework.web.filter.HttpPutFormContentFilter;
import org.springframework.web.filter.RequestContextFilter;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.AsyncSupportConfigurer;
import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
import org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.PathMatchConfigurer;
import org.springframework.web.servlet.config.annotation.ResourceChainRegistration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver;
import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping;
import org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver;
import org.springframework.web.servlet.i18n.FixedLocaleResolver;
import org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
import org.springframework.web.servlet.resource.AppCacheManifestTransformer;
import org.springframework.web.servlet.resource.GzipResourceResolver;
import org.springframework.web.servlet.resource.ResourceHttpRequestHandler;
import org.springframework.web.servlet.resource.ResourceResolver;
import org.springframework.web.servlet.resource.VersionResourceResolver;
import org.springframework.web.servlet.view.BeanNameViewResolver;
import org.springframework.web.servlet.view.ContentNegotiatingViewResolver;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for {@link EnableWebMvc Web MVC}.
 *
 * @author Phillip Webb
 * @author Dave Syer
 * @author Andy Wilkinson
 * @author Sébastien Deleuze
 * @author Eddú Meléndez
 * @author Stephane Nicoll
 * @author Kristine Jetzke
 * @author Bruce Brouwer
 */
@Configuration
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class })
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class,
        ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {

    public static final String DEFAULT_PREFIX = "";

    public static final String DEFAULT_SUFFIX = "";

    private static final String[] SERVLET_LOCATIONS = { "/" };

    @Bean
    @ConditionalOnMissingBean(HiddenHttpMethodFilter.class)
    public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() {
        return new OrderedHiddenHttpMethodFilter();
    }

    @Bean
    @ConditionalOnMissingBean(HttpPutFormContentFilter.class)
    @ConditionalOnProperty(prefix = "spring.mvc.formcontent.putfilter", name = "enabled", matchIfMissing = true)
    public OrderedHttpPutFormContentFilter httpPutFormContentFilter() {
        return new OrderedHttpPutFormContentFilter();
    }

    // Defined as a nested config to ensure WebMvcConfigurer is not read when not
    // on the classpath
    @Configuration
    @Import(EnableWebMvcConfiguration.class)
    @EnableConfigurationProperties({ WebMvcProperties.class, ResourceProperties.class })
    @Order(0)
    public static class WebMvcAutoConfigurationAdapter
            implements WebMvcConfigurer, ResourceLoaderAware {

        private static final Log logger = LogFactory.getLog(WebMvcConfigurer.class);

        private final ResourceProperties resourceProperties;

        private final WebMvcProperties mvcProperties;

        private final ListableBeanFactory beanFactory;

        private final ObjectProvider<HttpMessageConverters> messageConvertersProvider;

        final ResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer;

        private ResourceLoader resourceLoader;

        public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties,
                WebMvcProperties mvcProperties, ListableBeanFactory beanFactory,
                ObjectProvider<HttpMessageConverters> messageConvertersProvider,
                ObjectProvider<ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider) {
            this.resourceProperties = resourceProperties;
            this.mvcProperties = mvcProperties;
            this.beanFactory = beanFactory;
            this.messageConvertersProvider = messageConvertersProvider;
            this.resourceHandlerRegistrationCustomizer = resourceHandlerRegistrationCustomizerProvider
                    .getIfAvailable();
        }

        @Override
        public void setResourceLoader(ResourceLoader resourceLoader) {
            this.resourceLoader = resourceLoader;
        }

        @Override
        public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
            this.messageConvertersProvider.ifAvailable((customConverters) -> converters
                    .addAll(customConverters.getConverters()));
        }

        @Override
        public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
            Duration timeout = this.mvcProperties.getAsync().getRequestTimeout();
            if (timeout != null) {
                configurer.setDefaultTimeout(timeout.toMillis());
            }
        }

        @Override
        public void configurePathMatch(PathMatchConfigurer configurer) {
            configurer.setUseSuffixPatternMatch(
                    this.mvcProperties.getPathmatch().isUseSuffixPattern());
            configurer.setUseRegisteredSuffixPatternMatch(
                    this.mvcProperties.getPathmatch().isUseRegisteredSuffixPattern());
        }

        @Override
        public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
            WebMvcProperties.Contentnegotiation contentnegotiation = this.mvcProperties
                    .getContentnegotiation();
            configurer.favorPathExtension(contentnegotiation.isFavorPathExtension());
            configurer.favorParameter(contentnegotiation.isFavorParameter());
            if (contentnegotiation.getParameterName() != null) {
                configurer.parameterName(contentnegotiation.getParameterName());
            }
            Map<String, MediaType> mediaTypes = this.mvcProperties.getContentnegotiation()
                    .getMediaTypes();
            mediaTypes.forEach(configurer::mediaType);
        }

        @Bean
        @ConditionalOnMissingBean
        public InternalResourceViewResolver defaultViewResolver() {
            InternalResourceViewResolver resolver = new InternalResourceViewResolver();
            resolver.setPrefix(this.mvcProperties.getView().getPrefix());
            resolver.setSuffix(this.mvcProperties.getView().getSuffix());
            return resolver;
        }

        @Bean
        @ConditionalOnBean(View.class)
        @ConditionalOnMissingBean
        public BeanNameViewResolver beanNameViewResolver() {
            BeanNameViewResolver resolver = new BeanNameViewResolver();
            resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
            return resolver;
        }

        @Bean
        @ConditionalOnBean(ViewResolver.class)
        @ConditionalOnMissingBean(name = "viewResolver", value = ContentNegotiatingViewResolver.class)
        public ContentNegotiatingViewResolver viewResolver(BeanFactory beanFactory) {
            ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver();
            resolver.setContentNegotiationManager(
                    beanFactory.getBean(ContentNegotiationManager.class));
            // ContentNegotiatingViewResolver uses all the other view resolvers to locate
            // a view so it should have a high precedence
            resolver.setOrder(Ordered.HIGHEST_PRECEDENCE);
            return resolver;
        }

        @Bean
        @ConditionalOnMissingBean
        @ConditionalOnProperty(prefix = "spring.mvc", name = "locale")
        public LocaleResolver localeResolver() {
            if (this.mvcProperties
                    .getLocaleResolver() == WebMvcProperties.LocaleResolver.FIXED) {
                return new FixedLocaleResolver(this.mvcProperties.getLocale());
            }
            AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
            localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
            return localeResolver;
        }

        @Override
        public MessageCodesResolver getMessageCodesResolver() {
            if (this.mvcProperties.getMessageCodesResolverFormat() != null) {
                DefaultMessageCodesResolver resolver = new DefaultMessageCodesResolver();
                resolver.setMessageCodeFormatter(
                        this.mvcProperties.getMessageCodesResolverFormat());
                return resolver;
            }
            return null;
        }

        @Override
        public void addFormatters(FormatterRegistry registry) {
            for (Converter<?, ?> converter : getBeansOfType(Converter.class)) {
                registry.addConverter(converter);
            }
            for (GenericConverter converter : getBeansOfType(GenericConverter.class)) {
                registry.addConverter(converter);
            }
            for (Formatter<?> formatter : getBeansOfType(Formatter.class)) {
                registry.addFormatter(formatter);
            }
        }

        private <T> Collection<T> getBeansOfType(Class<T> type) {
            return this.beanFactory.getBeansOfType(type).values();
        }

        @Override
        public void addResourceHandlers(ResourceHandlerRegistry registry) {
            if (!this.resourceProperties.isAddMappings()) {
                logger.debug("Default resource handling disabled");
                return;
            }
            Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
            CacheControl cacheControl = this.resourceProperties.getCache()
                    .getCachecontrol().toHttpCacheControl();
            if (!registry.hasMappingForPattern("/webjars/**")) {
                customizeResourceHandlerRegistration(registry
                        .addResourceHandler("/webjars/**")
                        .addResourceLocations("classpath:/META-INF/resources/webjars/")
                        .setCachePeriod(getSeconds(cachePeriod))
                        .setCacheControl(cacheControl));
            }
            String staticPathPattern = this.mvcProperties.getStaticPathPattern();
            if (!registry.hasMappingForPattern(staticPathPattern)) {
                customizeResourceHandlerRegistration(
                        registry.addResourceHandler(staticPathPattern)
                                .addResourceLocations(getResourceLocations(
                                        this.resourceProperties.getStaticLocations()))
                                .setCachePeriod(getSeconds(cachePeriod))
                                .setCacheControl(cacheControl));
            }
        }

        private Integer getSeconds(Duration cachePeriod) {
            return (cachePeriod != null) ? (int) cachePeriod.getSeconds() : null;
        }

        @Bean
        public WelcomePageHandlerMapping welcomePageHandlerMapping(
                ApplicationContext applicationContext) {
            return new WelcomePageHandlerMapping(
                    new TemplateAvailabilityProviders(applicationContext),
                    applicationContext, getWelcomePage(),
                    this.mvcProperties.getStaticPathPattern());
        }

        static String[] getResourceLocations(String[] staticLocations) {
            String[] locations = new String[staticLocations.length
                    + SERVLET_LOCATIONS.length];
            System.arraycopy(staticLocations, 0, locations, 0, staticLocations.length);
            System.arraycopy(SERVLET_LOCATIONS, 0, locations, staticLocations.length,
                    SERVLET_LOCATIONS.length);
            return locations;
        }

        private Optional<Resource> getWelcomePage() {
            String[] locations = getResourceLocations(
                    this.resourceProperties.getStaticLocations());
            return Arrays.stream(locations).map(this::getIndexHtml)
                    .filter(this::isReadable).findFirst();
        }

        private Resource getIndexHtml(String location) {
            return this.resourceLoader.getResource(location + "index.html");
        }

        private boolean isReadable(Resource resource) {
            try {
                return resource.exists() && (resource.getURL() != null);
            }
            catch (Exception ex) {
                return false;
            }
        }

        private void customizeResourceHandlerRegistration(
                ResourceHandlerRegistration registration) {
            if (this.resourceHandlerRegistrationCustomizer != null) {
                this.resourceHandlerRegistrationCustomizer.customize(registration);
            }
        }

        @Bean
        @ConditionalOnMissingBean({ RequestContextListener.class,
                RequestContextFilter.class })
        public static RequestContextFilter requestContextFilter() {
            return new OrderedRequestContextFilter();
        }

        @Configuration
        @ConditionalOnProperty(value = "spring.mvc.favicon.enabled", matchIfMissing = true)
        public static class FaviconConfiguration implements ResourceLoaderAware {

            private final ResourceProperties resourceProperties;

            private ResourceLoader resourceLoader;

            public FaviconConfiguration(ResourceProperties resourceProperties) {
                this.resourceProperties = resourceProperties;
            }

            @Override
            public void setResourceLoader(ResourceLoader resourceLoader) {
                this.resourceLoader = resourceLoader;
            }

            @Bean
            public SimpleUrlHandlerMapping faviconHandlerMapping() {
                SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
                mapping.setOrder(Ordered.HIGHEST_PRECEDENCE + 1);
                mapping.setUrlMap(Collections.singletonMap("**/favicon.ico",
                        faviconRequestHandler()));
                return mapping;
            }

            @Bean
            public ResourceHttpRequestHandler faviconRequestHandler() {
                ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
                requestHandler.setLocations(resolveFaviconLocations());
                return requestHandler;
            }

            private List<Resource> resolveFaviconLocations() {
                String[] staticLocations = getResourceLocations(
                        this.resourceProperties.getStaticLocations());
                List<Resource> locations = new ArrayList<>(staticLocations.length + 1);
                Arrays.stream(staticLocations).map(this.resourceLoader::getResource)
                        .forEach(locations::add);
                locations.add(new ClassPathResource("/"));
                return Collections.unmodifiableList(locations);
            }

        }

    }

    /**
     * Configuration equivalent to {@code @EnableWebMvc}.
     */
    @Configuration
    public static class EnableWebMvcConfiguration extends DelegatingWebMvcConfiguration {

        private final WebMvcProperties mvcProperties;

        private final ListableBeanFactory beanFactory;

        private final WebMvcRegistrations mvcRegistrations;

        public EnableWebMvcConfiguration(
                ObjectProvider<WebMvcProperties> mvcPropertiesProvider,
                ObjectProvider<WebMvcRegistrations> mvcRegistrationsProvider,
                ListableBeanFactory beanFactory) {
            this.mvcProperties = mvcPropertiesProvider.getIfAvailable();
            this.mvcRegistrations = mvcRegistrationsProvider.getIfUnique();
            this.beanFactory = beanFactory;
        }

        @Bean
        @Override
        public RequestMappingHandlerAdapter requestMappingHandlerAdapter() {
            RequestMappingHandlerAdapter adapter = super.requestMappingHandlerAdapter();
            adapter.setIgnoreDefaultModelOnRedirect(this.mvcProperties == null
                    || this.mvcProperties.isIgnoreDefaultModelOnRedirect());
            return adapter;
        }

        @Override
        protected RequestMappingHandlerAdapter createRequestMappingHandlerAdapter() {
            if (this.mvcRegistrations != null
                    && this.mvcRegistrations.getRequestMappingHandlerAdapter() != null) {
                return this.mvcRegistrations.getRequestMappingHandlerAdapter();
            }
            return super.createRequestMappingHandlerAdapter();
        }

        @Bean
        @Primary
        @Override
        public RequestMappingHandlerMapping requestMappingHandlerMapping() {
            // Must be @Primary for MvcUriComponentsBuilder to work
            return super.requestMappingHandlerMapping();
        }

        @Bean
        @Override
        public FormattingConversionService mvcConversionService() {
            WebConversionService conversionService = new WebConversionService(
                    this.mvcProperties.getDateFormat());
            addFormatters(conversionService);
            return conversionService;
        }

        @Bean
        @Override
        public Validator mvcValidator() {
            if (!ClassUtils.isPresent("javax.validation.Validator",
                    getClass().getClassLoader())) {
                return super.mvcValidator();
            }
            return ValidatorAdapter.get(getApplicationContext(), getValidator());
        }

        @Override
        protected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {
            if (this.mvcRegistrations != null
                    && this.mvcRegistrations.getRequestMappingHandlerMapping() != null) {
                return this.mvcRegistrations.getRequestMappingHandlerMapping();
            }
            return super.createRequestMappingHandlerMapping();
        }

        @Override
        protected ConfigurableWebBindingInitializer getConfigurableWebBindingInitializer() {
            try {
                return this.beanFactory.getBean(ConfigurableWebBindingInitializer.class);
            }
            catch (NoSuchBeanDefinitionException ex) {
                return super.getConfigurableWebBindingInitializer();
            }
        }

        @Override
        protected ExceptionHandlerExceptionResolver createExceptionHandlerExceptionResolver() {
            if (this.mvcRegistrations != null && this.mvcRegistrations
                    .getExceptionHandlerExceptionResolver() != null) {
                return this.mvcRegistrations.getExceptionHandlerExceptionResolver();
            }
            return super.createExceptionHandlerExceptionResolver();
        }

        @Override
        protected void configureHandlerExceptionResolvers(
                List<HandlerExceptionResolver> exceptionResolvers) {
            super.configureHandlerExceptionResolvers(exceptionResolvers);
            if (exceptionResolvers.isEmpty()) {
                addDefaultHandlerExceptionResolvers(exceptionResolvers);
            }
            if (this.mvcProperties.isLogResolvedException()) {
                for (HandlerExceptionResolver resolver : exceptionResolvers) {
                    if (resolver instanceof AbstractHandlerExceptionResolver) {
                        ((AbstractHandlerExceptionResolver) resolver)
                                .setWarnLogCategory(resolver.getClass().getName());
                    }
                }
            }
        }

        @Bean
        @Override
        public ContentNegotiationManager mvcContentNegotiationManager() {
            ContentNegotiationManager manager = super.mvcContentNegotiationManager();
            List<ContentNegotiationStrategy> strategies = manager.getStrategies();
            ListIterator<ContentNegotiationStrategy> iterator = strategies.listIterator();
            while (iterator.hasNext()) {
                ContentNegotiationStrategy strategy = iterator.next();
                if (strategy instanceof PathExtensionContentNegotiationStrategy) {
                    iterator.set(new OptionalPathExtensionContentNegotiationStrategy(
                            strategy));
                }
            }
            return manager;
        }

    }

    @Configuration
    @ConditionalOnEnabledResourceChain
    static class ResourceChainCustomizerConfiguration {

        @Bean
        public ResourceChainResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer() {
            return new ResourceChainResourceHandlerRegistrationCustomizer();
        }

    }

    interface ResourceHandlerRegistrationCustomizer {

        void customize(ResourceHandlerRegistration registration);

    }

    private static class ResourceChainResourceHandlerRegistrationCustomizer
            implements ResourceHandlerRegistrationCustomizer {

        @Autowired
        private ResourceProperties resourceProperties = new ResourceProperties();

        @Override
        public void customize(ResourceHandlerRegistration registration) {
            ResourceProperties.Chain properties = this.resourceProperties.getChain();
            configureResourceChain(properties,
                    registration.resourceChain(properties.isCache()));
        }

        private void configureResourceChain(ResourceProperties.Chain properties,
                ResourceChainRegistration chain) {
            Strategy strategy = properties.getStrategy();
            if (strategy.getFixed().isEnabled() || strategy.getContent().isEnabled()) {
                chain.addResolver(getVersionResourceResolver(strategy));
            }
            if (properties.isGzipped()) {
                chain.addResolver(new GzipResourceResolver());
            }
            if (properties.isHtmlApplicationCache()) {
                chain.addTransformer(new AppCacheManifestTransformer());
            }
        }

        private ResourceResolver getVersionResourceResolver(
                ResourceProperties.Strategy properties) {
            VersionResourceResolver resolver = new VersionResourceResolver();
            if (properties.getFixed().isEnabled()) {
                String version = properties.getFixed().getVersion();
                String[] paths = properties.getFixed().getPaths();
                resolver.addFixedVersionStrategy(version, paths);
            }
            if (properties.getContent().isEnabled()) {
                String[] paths = properties.getContent().getPaths();
                resolver.addContentVersionStrategy(paths);
            }
            return resolver;
        }

    }

    /**
     * Decorator to make {@link PathExtensionContentNegotiationStrategy} optional
     * depending on a request attribute.
     */
    static class OptionalPathExtensionContentNegotiationStrategy
            implements ContentNegotiationStrategy {

        private static final String SKIP_ATTRIBUTE = PathExtensionContentNegotiationStrategy.class
                .getName() + ".SKIP";

        private final ContentNegotiationStrategy delegate;

        OptionalPathExtensionContentNegotiationStrategy(
                ContentNegotiationStrategy delegate) {
            this.delegate = delegate;
        }

        @Override
        public List<MediaType> resolveMediaTypes(NativeWebRequest webRequest)
                throws HttpMediaTypeNotAcceptableException {
            Object skip = webRequest.getAttribute(SKIP_ATTRIBUTE,
                    RequestAttributes.SCOPE_REQUEST);
            if (skip != null && Boolean.parseBoolean(skip.toString())) {
                return MEDIA_TYPE_ALL_LIST;
            }
            return this.delegate.resolveMediaTypes(webRequest);
        }

    }

}

视图解析：查看WebMvcAutoConfigurationAdapter中WebMvcProperties属性，可以看到，

spring.mvc.view.prefix=
spring.mvc.view.suffix=

静态资源：以及查看ResourceProperties，可以看到静态资源配置路径，任何一个位置即可。或者使用：spring.resources.static-locations=重新配置

    private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
            "classpath:/META-INF/resources/", "classpath:/resources/",
            "classpath:/static/", "classpath:/public/" };

静态资源：webjar默认

        @Override
        public void addResourceHandlers(ResourceHandlerRegistry registry) {
            if (!this.resourceProperties.isAddMappings()) {
                logger.debug("Default resource handling disabled");
                return;
            }
            Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
            CacheControl cacheControl = this.resourceProperties.getCache()
                    .getCachecontrol().toHttpCacheControl();
            if (!registry.hasMappingForPattern("/webjars/**")) {
                customizeResourceHandlerRegistration(registry
                        .addResourceHandler("/webjars/**")
                        .addResourceLocations("classpath:/META-INF/resources/webjars/")
                        .setCachePeriod(getSeconds(cachePeriod))
                        .setCacheControl(cacheControl));
            }

对带有“ewbjar”前缀资源访问将会在类路径中解析，可以使用maven中央仓库预先打包好JavaScript依赖。

WebJars是jar包格式的客户端JavaScript库。

地域管理

        @Bean
        @ConditionalOnMissingBean
        @ConditionalOnProperty(prefix = "spring.mvc", name = "locale")
        public LocaleResolver localeResolver() {
            if (this.mvcProperties
                    .getLocaleResolver() == WebMvcProperties.LocaleResolver.FIXED) {
                return new FixedLocaleResolver(this.mvcProperties.getLocale());
            }
            AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
            localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
            return localeResolver;
        }

默认只会处理一个地域，可以自定义：spring.mvc.locale

3.4、错误与转码配置

查看ErrorMvcAutoConfiguration源码

/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.autoconfigure.web.servlet.error;

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.Servlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.aop.framework.autoproxy.AutoProxyUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.boot.autoconfigure.AutoConfigureBefore;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionMessage;
import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.condition.SearchStrategy;
import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider;
import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProviders;
import org.springframework.boot.autoconfigure.web.ResourceProperties;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.autoconfigure.web.servlet.DispatcherServletPath;
import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.server.ErrorPage;
import org.springframework.boot.web.server.ErrorPageRegistrar;
import org.springframework.boot.web.server.ErrorPageRegistry;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;
import org.springframework.boot.web.servlet.error.ErrorAttributes;
import org.springframework.boot.web.servlet.error.ErrorController;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.expression.MapAccessor;
import org.springframework.core.Ordered;
import org.springframework.core.type.AnnotatedTypeMetadata;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.SimpleEvaluationContext;
import org.springframework.util.PropertyPlaceholderHelper.PlaceholderResolver;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.view.BeanNameViewResolver;
import org.springframework.web.util.HtmlUtils;

/**
 * {@link EnableAutoConfiguration Auto-configuration} to render errors via an MVC error
 * controller.
 *
 * @author Dave Syer
 * @author Andy Wilkinson
 * @author Stephane Nicoll
 */
@Configuration
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class })
// Load before the main WebMvcAutoConfiguration so that the error View is available
@AutoConfigureBefore(WebMvcAutoConfiguration.class)
@EnableConfigurationProperties({ ServerProperties.class, ResourceProperties.class })
public class ErrorMvcAutoConfiguration {

    private final ServerProperties serverProperties;

    private final DispatcherServletPath dispatcherServletPath;

    private final List<ErrorViewResolver> errorViewResolvers;

    public ErrorMvcAutoConfiguration(ServerProperties serverProperties,
            DispatcherServletPath dispatcherServletPath,
            ObjectProvider<List<ErrorViewResolver>> errorViewResolversProvider) {
        this.serverProperties = serverProperties;
        this.dispatcherServletPath = dispatcherServletPath;
        this.errorViewResolvers = errorViewResolversProvider.getIfAvailable();
    }

    @Bean
    @ConditionalOnMissingBean(value = ErrorAttributes.class, search = SearchStrategy.CURRENT)
    public DefaultErrorAttributes errorAttributes() {
        return new DefaultErrorAttributes(
                this.serverProperties.getError().isIncludeException());
    }

    @Bean
    @ConditionalOnMissingBean(value = ErrorController.class, search = SearchStrategy.CURRENT)
    public BasicErrorController basicErrorController(ErrorAttributes errorAttributes) {
        return new BasicErrorController(errorAttributes, this.serverProperties.getError(),
                this.errorViewResolvers);
    }

    @Bean
    public ErrorPageCustomizer errorPageCustomizer() {
        return new ErrorPageCustomizer(this.serverProperties, this.dispatcherServletPath);
    }

    @Bean
    public static PreserveErrorControllerTargetClassPostProcessor preserveErrorControllerTargetClassPostProcessor() {
        return new PreserveErrorControllerTargetClassPostProcessor();
    }

    @Configuration
    static class DefaultErrorViewResolverConfiguration {

        private final ApplicationContext applicationContext;

        private final ResourceProperties resourceProperties;

        DefaultErrorViewResolverConfiguration(ApplicationContext applicationContext,
                ResourceProperties resourceProperties) {
            this.applicationContext = applicationContext;
            this.resourceProperties = resourceProperties;
        }

        @Bean
        @ConditionalOnBean(DispatcherServlet.class)
        @ConditionalOnMissingBean
        public DefaultErrorViewResolver conventionErrorViewResolver() {
            return new DefaultErrorViewResolver(this.applicationContext,
                    this.resourceProperties);
        }

    }

    @Configuration
    @ConditionalOnProperty(prefix = "server.error.whitelabel", name = "enabled", matchIfMissing = true)
    @Conditional(ErrorTemplateMissingCondition.class)
    protected static class WhitelabelErrorViewConfiguration {

        private final SpelView defaultErrorView = new SpelView(
                "<html><body><h1>Whitelabel Error Page</h1>"
                        + "<p>This application has no explicit mapping for /error, so you are seeing this as a fallback.</p>"
                        + "<div id='created'>${timestamp}</div>"
                        + "<div>There was an unexpected error (type=${error}, status=${status}).</div>"
                        + "<div>${message}</div></body></html>");

        @Bean(name = "error")
        @ConditionalOnMissingBean(name = "error")
        public View defaultErrorView() {
            return this.defaultErrorView;
        }

        // If the user adds @EnableWebMvc then the bean name view resolver from
        // WebMvcAutoConfiguration disappears, so add it back in to avoid disappointment.
        @Bean
        @ConditionalOnMissingBean
        public BeanNameViewResolver beanNameViewResolver() {
            BeanNameViewResolver resolver = new BeanNameViewResolver();
            resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
            return resolver;
        }

    }

    /**
     * {@link SpringBootCondition} that matches when no error template view is detected.
     */
    private static class ErrorTemplateMissingCondition extends SpringBootCondition {

        @Override
        public ConditionOutcome getMatchOutcome(ConditionContext context,
                AnnotatedTypeMetadata metadata) {
            ConditionMessage.Builder message = ConditionMessage
                    .forCondition("ErrorTemplate Missing");
            TemplateAvailabilityProviders providers = new TemplateAvailabilityProviders(
                    context.getClassLoader());
            TemplateAvailabilityProvider provider = providers.getProvider("error",
                    context.getEnvironment(), context.getClassLoader(),
                    context.getResourceLoader());
            if (provider != null) {
                return ConditionOutcome
                        .noMatch(message.foundExactly("template from " + provider));
            }
            return ConditionOutcome
                    .match(message.didNotFind("error template view").atAll());
        }

    }

    /**
     * Simple {@link View} implementation that resolves variables as SpEL expressions.
     */
    private static class SpelView implements View {

        private static final Log logger = LogFactory.getLog(SpelView.class);

        private final NonRecursivePropertyPlaceholderHelper helper;

        private final String template;

        private volatile Map<String, Expression> expressions;

        SpelView(String template) {
            this.helper = new NonRecursivePropertyPlaceholderHelper("${", "}");
            this.template = template;
        }

        @Override
        public String getContentType() {
            return "text/html";
        }

        @Override
        public void render(Map<String, ?> model, HttpServletRequest request,
                HttpServletResponse response) throws Exception {
            if (response.isCommitted()) {
                String message = getMessage(model);
                logger.error(message);
                return;
            }
            if (response.getContentType() == null) {
                response.setContentType(getContentType());
            }
            PlaceholderResolver resolver = new ExpressionResolver(getExpressions(),
                    model);
            String result = this.helper.replacePlaceholders(this.template, resolver);
            response.getWriter().append(result);
        }

        private String getMessage(Map<String, ?> model) {
            Object path = model.get("path");
            String message = "Cannot render error page for request [" + path + "]";
            if (model.get("message") != null) {
                message += " and exception [" + model.get("message") + "]";
            }
            message += " as the response has already been committed.";
            message += " As a result, the response may have the wrong status code.";
            return message;
        }

        private Map<String, Expression> getExpressions() {
            if (this.expressions == null) {
                synchronized (this) {
                    ExpressionCollector expressionCollector = new ExpressionCollector();
                    this.helper.replacePlaceholders(this.template, expressionCollector);
                    this.expressions = expressionCollector.getExpressions();
                }
            }
            return this.expressions;
        }

    }

    /**
     * {@link PlaceholderResolver} to collect placeholder expressions.
     */
    private static class ExpressionCollector implements PlaceholderResolver {

        private final SpelExpressionParser parser = new SpelExpressionParser();

        private final Map<String, Expression> expressions = new HashMap<>();

        @Override
        public String resolvePlaceholder(String name) {
            this.expressions.put(name, this.parser.parseExpression(name));
            return null;
        }

        public Map<String, Expression> getExpressions() {
            return Collections.unmodifiableMap(this.expressions);
        }

    }

    /**
     * SpEL based {@link PlaceholderResolver}.
     */
    private static class ExpressionResolver implements PlaceholderResolver {

        private final Map<String, Expression> expressions;

        private final EvaluationContext context;

        ExpressionResolver(Map<String, Expression> expressions, Map<String, ?> map) {
            this.expressions = expressions;
            this.context = getContext(map);
        }

        private EvaluationContext getContext(Map<String, ?> map) {
            return SimpleEvaluationContext.forPropertyAccessors(new MapAccessor())
                    .withRootObject(map).build();
        }

        @Override
        public String resolvePlaceholder(String placeholderName) {
            Expression expression = this.expressions.get(placeholderName);
            Object expressionValue = (expression != null)
                    ? expression.getValue(this.context) : null;
            return escape(expressionValue);
        }

        private String escape(Object value) {
            return HtmlUtils.htmlEscape((value != null) ? value.toString() : null);
        }

    }

    /**
     * {@link WebServerFactoryCustomizer} that configures the server's error pages.
     */
    private static class ErrorPageCustomizer implements ErrorPageRegistrar, Ordered {

        private final ServerProperties properties;

        private final DispatcherServletPath dispatcherServletPath;

        protected ErrorPageCustomizer(ServerProperties properties,
                DispatcherServletPath dispatcherServletPath) {
            this.properties = properties;
            this.dispatcherServletPath = dispatcherServletPath;
        }

        @Override
        public void registerErrorPages(ErrorPageRegistry errorPageRegistry) {
            ErrorPage errorPage = new ErrorPage(this.dispatcherServletPath
                    .getRelativePath(this.properties.getError().getPath()));
            errorPageRegistry.addErrorPages(errorPage);
        }

        @Override
        public int getOrder() {
            return 0;
        }

    }

    /**
     * {@link BeanFactoryPostProcessor} to ensure that the target class of ErrorController
     * MVC beans are preserved when using AOP.
     */
    static class PreserveErrorControllerTargetClassPostProcessor
            implements BeanFactoryPostProcessor {

        @Override
        public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
                throws BeansException {
            String[] errorControllerBeans = beanFactory
                    .getBeanNamesForType(ErrorController.class, false, false);
            for (String errorControllerBean : errorControllerBeans) {
                try {
                    beanFactory.getBeanDefinition(errorControllerBean).setAttribute(
                            AutoProxyUtils.PRESERVE_TARGET_CLASS_ATTRIBUTE, Boolean.TRUE);
                }
                catch (Throwable ex) {
                    // Ignore
                }
            }
        }

    }

}

　　定义了一个Bean，即DefaultErrorAttributes，他通过特定的属性暴露了有用的错误信息，这些属性包括状态、错误码和相关的栈跟踪信息

　　定义了一个BasicErrorController的bean，负责展示错误页。

　　允许我们将spring boot的whitelabel错误页设置为无效，server.error.whitelabel.enabled=false

　　还可以以借助模板引擎提供自己的错误页面。他的名字是error.html，ErrorTemplateMissingCondition条件会对此进行检查。

转码：HttpEncodingAutoConfiguration，他是通过Spring的CharacterEncodingFilter类实现，通过spring.http.encoding.charset=UTF-8;配置。如果禁用：spring.http.encoding.enabled=false

3.5、嵌入式Servlet容器配置

查看：EmbeddedWebServerFactoryCustomizerAutoConfiguration代码：

/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.autoconfigure.web.embedded;

import io.undertow.Undertow;
import org.apache.catalina.startup.Tomcat;
import org.apache.coyote.UpgradeProtocol;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.util.Loader;
import org.eclipse.jetty.webapp.WebAppContext;
import org.xnio.SslClientAuthMode;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for embedded servlet and reactive
 * web servers customizations.
 *
 * @author Phillip Webb
 * @since 2.0.0
 */
@Configuration
@EnableConfigurationProperties(ServerProperties.class)
public class EmbeddedWebServerFactoryCustomizerAutoConfiguration {

    @ConditionalOnClass({ Tomcat.class, UpgradeProtocol.class })
    public static class TomcatWebServerFactoryCustomizerConfiguration {

        @Bean
        public TomcatWebServerFactoryCustomizer tomcatWebServerFactoryCustomizer(
                Environment environment, ServerProperties serverProperties) {
            return new TomcatWebServerFactoryCustomizer(environment, serverProperties);
        }

    }

    /**
     * Nested configuration if Jetty is being used.
     */
    @Configuration
    @ConditionalOnClass({ Server.class, Loader.class, WebAppContext.class })
    public static class JettyWebServerFactoryCustomizerConfiguration {

        @Bean
        public JettyWebServerFactoryCustomizer jettyWebServerFactoryCustomizer(
                Environment environment, ServerProperties serverProperties) {
            return new JettyWebServerFactoryCustomizer(environment, serverProperties);
        }

    }

    /**
     * Nested configuration if Undertow is being used.
     */
    @Configuration
    @ConditionalOnClass({ Undertow.class, SslClientAuthMode.class })
    public static class UndertowWebServerFactoryCustomizerConfiguration {

        @Bean
        public UndertowWebServerFactoryCustomizer undertowWebServerFactoryCustomizer(
                Environment environment, ServerProperties serverProperties) {
            return new UndertowWebServerFactoryCustomizer(environment, serverProperties);
        }

    }

}

 可以看待spring-boot默认支持tomcat，tc-server,Jetty,Undertow web容器。

3.5.1、http端口

使用：server.port=8080配置，-1禁用http，0随机端口启动应用，便于测试

3.5.2、ssl配置

server.port=8443 
server.ssl.key-store=classpath:keystore.jks
server.ssl.key-store-password=secret
server.ssl.key-password=another-secret

3.5.3、其他配置

在JacksonAutoConfiguration中，声明使用Jackson进行json序列化

在HttpMessageConvertersAutoConfiguration中，声明了默认的HttpMessageConverter;

在JmxAutoConfiguration中，声明了JMX功能。

　　禁用spring.jmx.enabled=false

四、gradle构建多模块项目

1、可以使用工具或者命令创建

mkdir springboot-mm 
cd springboot-mm 
gradle init

目录结构：

修改gradleParent的相关配置

settings.gradle

rootProject.name = 'gradle-mvc4'

include 'demo01-thymeleaf'

build.gradle

allprojects {
    ext {
        springBootVersion = '2.0.7.RELEASE'
    }
    apply plugin: 'java'
    apply plugin: 'idea'


    // JVM 版本号要求
    sourceCompatibility = 1.8
    targetCompatibility = 1.8

    group = 'com.github.bjlhx15.gradle'
    version = '0.0.1-SNAPSHOT'

    // java编译的时候缺省状态下会因为中文字符而失败
    [compileJava,compileTestJava,javadoc]*.options*.encoding = 'UTF-8'

    repositories {
        mavenCentral()
    }

    dependencies {
        implementation 'org.springframework.boot:spring-boot-starter-web'
        compile group: 'org.springframework.boot', name: 'spring-boot-starter-thymeleaf', version: '2.0.7.RELEASE'
        testImplementation 'org.springframework.boot:spring-boot-starter-test'
    }
}

子项目build.gradle

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}

apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'

archivesBaseName = 'demo01-thymeleaf'

 代码参看：https://github.com/bjlhx15/gradle-mvc4