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spring-boo hello world程序

作为一个程序猿,使用了spring好多年,现在有了spring-boot,也想尝尝鲜。

初听spring-boot,觉得很神秘,实际上就是集合了很多组件,再加上一些boot开发的启动和粘合程序。 个人见解,不一定对。

构建过程

使用 Spring Initializr ,我使用idea构建的,在新项目里面有一个Spring Initializr 选项,如图:

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设置项目属性,如图:

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选择spring-boot组件: 

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设置项目名: 

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完成就可以了

第一个程序

新建Java程序

package com.sun.boot;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.web.bind.annotation.*;@RestController@EnableAutoConfigurationpublic class Application {    @RequestMapping("/helloworld")    public String home() {        return "Hello World!";    }    public static void main(String[] args) {        SpringApplication.run(Application.class, args);    }}

查看build.gradle文件

buildscript {    ext {        springBootVersion = ‘1.5.4.RELEASE‘    }    repositories {        mavenCentral()    }    dependencies {        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")    }}apply plugin: ‘java‘apply plugin: ‘eclipse‘apply plugin: ‘org.springframework.boot‘version = ‘0.0.1-SNAPSHOT‘sourceCompatibility = 1.8repositories {    mavenCentral()}dependencies {    compile(‘org.springframework.boot:spring-boot-starter-web‘)    runtime(‘mysql:mysql-connector-java‘)    testCompile(‘org.springframework.boot:spring-boot-starter-test‘)}

程序结构如下: 

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运行

运行Application,输出如下:

  .   ____          _            __ _ _ /\\ / ___‘_ __ _ _(_)_ __  __ _ \ \ \ ( ( )\___ | ‘_ | ‘_| | ‘_ \/ _` | \ \ \  \\/  ___)| |_)| | | | | || (_| |  ) ) ) )  ‘  |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot ::        (v1.5.4.RELEASE)2017-07-19 08:22:36.552  INFO 8372 --- [           main] com.sun.boot.Application                 : Starting Application on sunzuoquan-Inspiron-7466 with PID 8372 (/home/sunzuoquan/IdeaProjects/demo/build/classes/java/main started by sunzuoquan in /home/sunzuoquan/IdeaProjects/demo)2017-07-19 08:22:36.583  INFO 8372 --- [           main] com.sun.boot.Application                 : No active profile set, falling back to default profiles: default2017-07-19 08:22:37.041  INFO 8372 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@43bd930a: startup date [Wed Jul 19 08:22:36 CST 2017]; root of context hierarchy2017-07-19 08:22:42.185  INFO 8372 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)2017-07-19 08:22:42.210  INFO 8372 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]2017-07-19 08:22:42.211  INFO 8372 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.152017-07-19 08:22:42.747  INFO 8372 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext2017-07-19 08:22:42.748  INFO 8372 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 5760 ms2017-07-19 08:22:42.877  INFO 8372 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: ‘dispatcherServlet‘ to [/]2017-07-19 08:22:42.880  INFO 8372 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: ‘characterEncodingFilter‘ to: [/*]2017-07-19 08:22:42.880  INFO 8372 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: ‘hiddenHttpMethodFilter‘ to: [/*]2017-07-19 08:22:42.880  INFO 8372 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: ‘httpPutFormContentFilter‘ to: [/*]2017-07-19 08:22:42.881  INFO 8372 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: ‘requestContextFilter‘ to: [/*]2017-07-19 08:22:43.338  INFO 8372 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@43bd930a: startup date [Wed Jul 19 08:22:36 CST 2017]; root of context hierarchy2017-07-19 08:22:43.401  INFO 8372 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/helloworld]}" onto public java.lang.String com.sun.boot.Application.home()2017-07-19 08:22:43.405  INFO 8372 --- [           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)2017-07-19 08:22:43.405  INFO 8372 --- [           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)2017-07-19 08:22:43.421  INFO 8372 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-07-19 08:22:43.421  INFO 8372 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-07-19 08:22:43.440  INFO 8372 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-07-19 08:22:43.634  INFO 8372 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup2017-07-19 08:22:44.043  INFO 8372 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)2017-07-19 08:22:44.065  INFO 8372 --- [           main] com.sun.boot.Application                 : Started Application in 9.217 seconds (JVM running for 15.872)

从日志可以看出,Tomcat started on port(s): 8080,spring-boot内部启动了tomcat,监听8080端口。
打开浏览器,访问:http://localhost:8080/helloworld
浏览器输出如下:

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spring-boo hello world程序