SpringBoot-hello world

本节内容包含SpringBoot的开发环境配置以及第一个HelloWorld

准备环境：jdk1.8 + maven3.3.9 + eclipse

1. 新建Maven项目

2. 修改pom.xml文件

引入父类包以及spring-web的依赖包

  <!-- 引用 springboot-parent，实现了很多jar依赖管理 -->
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.9.RELEASE</version>
  </parent>
  <dependencies>
      <!-- 由于sprintboot默认引用了springmvc，所以这里只需要引用spring-web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
  </dependencies>

3. 在src/main/java目录下创建controller包，以及TestController文件

TestController.java文件内容如下：

package com.king.controller;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@EnableAutoConfiguration
public class TestController {
    
    
    @RequestMapping("/hello")
    public String hello(){
        return "Hello world!";
    }
    
    public static void main(String[] args) {
        SpringApplication.run(TestController.class, args);
    }
    

}

4. 在TestController中右键run as Java Application

然后在控制台中看到如下信息：

  .   ____          _            __ _ _
 /\ / ___'_ __ _ _(_)_ __  __ _    
( ( )\___ | '_ | '_| | '_ / _` |    
 \/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.9.RELEASE)

2018-01-28 22:45:03.463  INFO 171392 --- [           main] com.king.controller.TestController       : Starting TestController on KingWang with PID 171392 (D:workspaceworkspace_j2eespringboot	argetclasses started by Administrator in D:workspaceworkspace_j2eespringboot)
2018-01-28 22:45:03.467  INFO 171392 --- [           main] com.king.controller.TestController       : No active profile set, falling back to default profiles: default
2018-01-28 22:45:03.542  INFO 171392 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@5e955596: startup date [Sun Jan 28 22:45:03 CST 2018]; root of context hierarchy
2018-01-28 22:45:06.660  INFO 171392 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2018-01-28 22:45:06.684  INFO 171392 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2018-01-28 22:45:06.690  INFO 171392 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.23
2018-01-28 22:45:06.919  INFO 171392 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2018-01-28 22:45:06.920  INFO 171392 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 3383 ms
2018-01-28 22:45:07.296  INFO 171392 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2018-01-28 22:45:07.303  INFO 171392 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-01-28 22:45:07.307  INFO 171392 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-01-28 22:45:07.314  INFO 171392 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-01-28 22:45:07.315  INFO 171392 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2018-01-28 22:45:08.056  INFO 171392 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@5e955596: startup date [Sun Jan 28 22:45:03 CST 2018]; root of context hierarchy
2018-01-28 22:45:08.189  INFO 171392 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello]}" onto public java.lang.String com.king.controller.TestController.hello()
2018-01-28 22:45:08.199  INFO 171392 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-01-28 22:45:08.199  INFO 171392 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-01-28 22:45:08.250  INFO 171392 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-01-28 22:45:08.250  INFO 171392 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-01-28 22:45:08.325  INFO 171392 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-01-28 22:45:08.849  INFO 171392 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-01-28 22:45:09.071  INFO 171392 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2018-01-28 22:45:09.079  INFO 171392 --- [           main] com.king.controller.TestController       : Started TestController in 6.343 seconds (JVM running for 7.083)

5. 在浏览器中输入http://localhost:8080/hello即可

 

到此，一个简单的springboot项目完成。。。

使用springboot开开发java项目居然如此简单，

省去了ssm中的那些繁琐的xml配置。

内置了tomcat服务器，

直接生成一个可执行的jar文件，

所以我们直接通过run命令即可执行。

好了，夸奖springboot到此。