SpringBoot之SpringMVC自动配置概览和静态资源处理
SpringBoot之SpringMVC自动配置和静态资源设置
一、SpringMVC自动配置概览
Spring Boot provides auto-configuration for Spring MVC that works well with most applications.(大多场景我们都无需自定义配置)
The auto-configuration adds the following features on top of Spring’s defaults:
-
Inclusion of
ContentNegotiatingViewResolver
andBeanNameViewResolver
beans. -
- 内容协商视图解析器和BeanName视图解析器
-
Support for serving static resources, including support for WebJars (covered later in this document)).
-
- 静态资源(包括webjars)
-
Automatic registration of
Converter
,GenericConverter
, andFormatter
beans. -
- 自动注册
Converter,GenericConverter,Formatter
- 自动注册
-
Support for
HttpMessageConverters
(covered later in this document). -
- 支持
HttpMessageConverters
(后来我们配合内容协商理解原理)
- 支持
-
Automatic registration of
MessageCodesResolver
(covered later in this document). -
- 自动注册
MessageCodesResolver
(国际化用)
- 自动注册
-
Static
index.html
support. -
- 静态index.html 页支持
-
Custom
Favicon
support (covered later in this document). -
- 自定义
Favicon
- 自定义
-
Automatic use of a
ConfigurableWebBindingInitializer
bean (covered later in this document). -
- 自动使用
ConfigurableWebBindingInitializer
,(DataBinder负责将请求数据绑定到JavaBean上)
- 自动使用
If you want to keep those Spring Boot MVC customizations and make more MVC customizations (interceptors, formatters, view controllers, and other features), you can add your own
@Configuration
class of typeWebMvcConfigurer
but without@EnableWebMvc
.
不用@EnableWebMvc注解。使用 **@Configuration**
+ **WebMvcConfigurer**
自定义规则
If you want to provide custom instances of
RequestMappingHandlerMapping
,RequestMappingHandlerAdapter
, orExceptionHandlerExceptionResolver
, and still keep the Spring Boot MVC customizations, you can declare a bean of typeWebMvcRegistrations
and use it to provide custom instances of those components.
声明 **WebMvcRegistrations**
改变默认底层组件
If you want to take complete control of Spring MVC, you can add your own
@Configuration
annotated with@EnableWebMvc
, or alternatively add your own@Configuration
-annotatedDelegatingWebMvcConfiguration
as described in the Javadoc of@EnableWebMvc
.
使用 **@EnableWebMvc+@Configuration+DelegatingWebMvcConfiguration 全面接管SpringMVC**
二、简单功能分析
2.1、静态资源访问
1、静态资源目录
只要静态资源放在类路径下: called /static
(or /public
or /resources
or /META-INF/resources
访问 : 当前项目根路径/ + 静态资源名
原理: 静态映射/**。
请求进来,先去找Controller看能不能处理。不能处理的所有请求又都交给静态资源处理器。静态资源也找不到则响应404页面
改变默认的静态资源路径
spring:
mvc:
static-path-pattern: /res/**
resources:
static-locations: [classpath:/haha/]
2、静态资源访问前缀
默认无前缀:/**
spring:
mvc:
static-path-pattern: /res/**
当前项目 + static-path-pattern + 静态资源名 = 静态资源文件夹下找
3、webjar
自动映射 /webjars/**
<dependency>
<groupId>org.webjars</groupId>
<artifactId>jquery</artifactId>
<version>3.5.1</version>
</dependency>
访问地址:http://localhost:8080/webjars/jquery/3.5.1/jquery.js 后面地址要按照依赖里面的包路径
2.2、欢迎页支持
-
静态资源路径下 index.html
-
- 可以配置静态资源路径
- 但是不可以配置静态资源的访问前缀。否则导致 index.html不能被默认访问
spring:
# mvc:
# static-path-pattern: /res/** 这个会导致welcome page功能失效
resources:
static-locations: [classpath:/haha/]
- controller能处理/index
2.3、自定义 Favicon
favicon.ico 放在静态资源目录下即可。
spring:
# mvc:
# static-path-pattern: /res/** 这个会导致 Favicon 功能失效
2.4、静态资源配置原理
- SpringBoot启动默认加载 xxxAutoConfiguration 类(自动配置类)
- SpringMVC功能的自动配置类 WebMvcAutoConfiguration,生效
@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class })
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class,
ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {}
- 给容器中配了什么。
@Configuration(proxyBeanMethods = false)
@Import(EnableWebMvcConfiguration.class)
// 默认导入了WebMvcProperties和ResourceProperties
@EnableConfigurationProperties({ WebMvcProperties.class, ResourceProperties.class })
@Order(0)
public static class WebMvcAutoConfigurationAdapter implements WebMvcConfigurer {}
- 配置文件的相关属性和xxx进行了绑定。WebMvcPropertiesspring.mvc、ResourcePropertiesspring.resources
1、配置类只有一个有参构造器
//有参构造器所有参数的值都会从容器中确定
//ResourceProperties resourceProperties;获取和spring.resources绑定的所有的值的对象
//WebMvcProperties mvcProperties 获取和spring.mvc绑定的所有的值的对象
//ListableBeanFactory beanFactory Spring的beanFactory
//HttpMessageConverters 找到所有的HttpMessageConverters
//ResourceHandlerRegistrationCustomizer 找到 资源处理器的自定义器。=========
//DispatcherServletPath
//ServletRegistrationBean 给应用注册Servlet、Filter....
public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties, WebMvcProperties mvcProperties,
ListableBeanFactory beanFactory, ObjectProvider<HttpMessageConverters> messageConvertersProvider,
ObjectProvider<ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider,
ObjectProvider<DispatcherServletPath> dispatcherServletPath,
ObjectProvider<ServletRegistrationBean<?>> servletRegistrations) {
this.resourceProperties = resourceProperties;
this.mvcProperties = mvcProperties;
this.beanFactory = beanFactory;
this.messageConvertersProvider = messageConvertersProvider;
this.resourceHandlerRegistrationCustomizer = resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
this.dispatcherServletPath = dispatcherServletPath;
this.servletRegistrations = servletRegistrations;
}
2、资源处理的默认规则
@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();
//webjars的规则
if (!registry.hasMappingForPattern("/webjars/**")) {
customizeResourceHandlerRegistration(registry.addResourceHandler("/webjars/**")
.addResourceLocations("classpath:/META-INF/resources/webjars/")
.setCachePeriod(getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
// 静态路径处理策略
String staticPathPattern = this.mvcProperties.getStaticPathPattern();
if (!registry.hasMappingForPattern(staticPathPattern)) {
customizeResourceHandlerRegistration(registry.addResourceHandler(staticPathPattern)
.addResourceLocations(getResourceLocations(this.resourceProperties.getStaticLocations())) .setCachePeriod(getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
}
spring:
# mvc:
# static-path-pattern: /res/**
/**
resources:
add-mappings: false 禁用所有静态资源规则
@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties {
private static final String[] CLASSPATH_RESOURCE_LOCATIONS = { "classpath:/META-INF/resources/",
"classpath:/resources/", "classpath:/static/", "classpath:/public/" };
/**
* Locations of static resources. Defaults to classpath:[/META-INF/resources/,
* /resources/, /static/, /public/].
*/
private String[] staticLocations = CLASSPATH_RESOURCE_LOCATIONS;
*/
3、欢迎页的处理规则
// HandlerMapping:处理器映射。保存了每一个Handler能处理哪些请求。
@Bean
public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext,
FormattingConversionService mvcConversionService, ResourceUrlProvider mvcResourceUrlProvider) {
// 看一下创建时候的规则
WelcomePageHandlerMapping welcomePageHandlerMapping = new WelcomePageHandlerMapping(
new TemplateAvailabilityProviders(applicationContext), applicationContext, getWelcomePage(),
this.mvcProperties.getStaticPathPattern());
welcomePageHandlerMapping.setInterceptors(getInterceptors(mvcConversionService, mvcResourceUrlProvider));
welcomePageHandlerMapping.setCorsConfigurations(getCorsConfigurations());
return welcomePageHandlerMapping;
}
// ====================================================
WelcomePageHandlerMapping(TemplateAvailabilityProviders templateAvailabilityProviders,
ApplicationContext applicationContext, Optional<Resource> welcomePage, String staticPathPattern) {
//要用欢迎页功能,必须是/**
if (welcomePage.isPresent() && "/**".equals(staticPathPattern)) {
logger.info("Adding welcome page: " + welcomePage.get());
setRootViewName("forward:index.html");
}
else if (welcomeTemplateExists(templateAvailabilityProviders, applicationContext)) {
// 调用Controller /index
logger.info("Adding welcome page template: index");
setRootViewName("index");
}
}
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