spring-boot之hello word
spring boot环境的搭建，从spring官网下一个demo就可以了，地址：http://start.spring.io/。
1.pom.xml的配置(只需要加入一个spring boot启动父依赖即可)
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>springboot</groupId> <artifactId>springboot-helloworld</artifactId> <version>0.0.1-SNAPSHOT</version> <name>springboot-helloworld :: HelloWorld Demo</name> <!-- Spring Boot 启动父依赖 --> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.3.3.RELEASE</version> </parent> <dependencies> <!-- Spring Boot web依赖 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- Junit --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> </dependency> </dependencies> </project>
2.Controller层
package com.example.demo.controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class HelloWorldController { @RequestMapping("/") public String sayHello(){ return "Hello,World!"; } }
@RestController和@RequestMapping注解是来自SpringMVC的注解，它们不是SpringBoot的特定部分。
1）@RestController：提供实现了REST API，可以服务JSON,XML或者其他。这里是以String的形式渲染出结果。
2）@RequestMapping：提供路由信息，"/“路径的HTTP Request都会被映射到sayHello方法进行处理。
3.启动应用类
开箱即用
package com.example.demo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); } }
1）@SpringBootApplication：Spring Boot 应用的标识
2）Application很简单，一个main函数作为主入口。SpringApplication引导应用，并将Application本身作为参数传递给run方法。具体run方法会启动嵌入式的Tomcat并初始化Spring环境及其各Spring组件。
4.controller层测试类
一个好的程序，不能缺少好的UT。针对HelloWorldController的UT如下：
package com.example.controller; import org.junit.Test; import com.example.demo.controller.HelloWorldController; public class HelloWorldControllerTest { @Test public void testSayHello(){ System.out.println(new HelloWorldController().sayHello()); } }
5.运行
Just Run的宗旨，运行很简单，直接右键Run运行Application类。同样你也可以Debug Run。可以在控制台中看到：
. ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.1.0.RELEASE) 2018-11-19 22:05:34.642 INFO 11808 --- [ main] com.example.demo.DemoApplication : Starting DemoApplication on LAPTOP-8V3CCI0E with PID 11808 (started by 李玉龙 in D:\工作\work-springboot\demo) 2018-11-19 22:05:34.644 INFO 11808 --- [ main] com.example.demo.DemoApplication : No active profile set, falling back to default profiles: default 2018-11-19 22:05:35.578 INFO 11808 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http) 2018-11-19 22:05:35.592 INFO 11808 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] 2018-11-19 22:05:35.592 INFO 11808 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/9.0.12 2018-11-19 22:05:35.600 INFO 11808 --- [ main] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [C:\Program Files\Java\jre1.8.0_101\bin;C:\windows\Sun\Java\bin;C:\windows\system32;C:\windows;C:/Program Files/Java/jre1.8.0_101/bin/server;C:/Program Files/Java/jre1.8.0_101/bin;C:/Program Files/Java/jre1.8.0_101/lib/amd64;C:\ProgramData\Oracle\Java\javapath;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\iCLS\;C:\Program Files\Intel\Intel(R) Management Engine Components\iCLS\;C:\windows\system32;C:\windows;C:\windows\System32\Wbem;C:\windows\System32\WindowsPowerShell\v1.0\;C:\windows\System32\OpenSSH\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\Program Files\Java\jdk1.8.0_101\bin;C:\Users\liyulong\AppData\Local\Microsoft\WindowsApps;;D:\工作\软件\eclipse;;.] 2018-11-19 22:05:35.704 INFO 11808 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext 2018-11-19 22:05:35.704 INFO 11808 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1022 ms 2018-11-19 22:05:35.720 INFO 11808 --- [ main] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/] 2018-11-19 22:05:35.722 INFO 11808 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*] 2018-11-19 22:05:35.723 INFO 11808 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*] 2018-11-19 22:05:35.723 INFO 11808 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'formContentFilter' to: [/*] 2018-11-19 22:05:35.723 INFO 11808 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*] 2018-11-19 22:05:35.882 INFO 11808 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor' 2018-11-19 22:05:36.020 INFO 11808 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path '' 2018-11-19 22:05:36.022 INFO 11808 --- [ main] com.example.demo.DemoApplication : Started DemoApplication in 1.611 seconds (JVM running for 1.999) 2018-11-19 22:05:40.145 INFO 11808 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet' 2018-11-19 22:05:40.145 INFO 11808 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet' 2018-11-19 22:05:40.149 INFO 11808 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 4 ms
然后访问 http://localhost:8080/ ,即可在页面中看到Spring Boot对你 say hello
