springBoot入门

1、springBoot是什么
在我们使用SSM开发的时候，我们需要将SSM以xml配置的形式进行整合，同时会发现spring本身的配置就占了很大部分、会导致我们需要对项目的配置文件的进行分类管理，这个时候springBoot就应运而生，专门帮我们管理配置文件。
但是实际上现在springBoot已经发展成了一种开发体系，集成了我们的spring的核心工厂，springMVC、JPA、还有一些spring的功能，同时集成了一个tomcat服务器。我们只需要利用一个springBoot就可以完成整套spring应用的开发，

2、springBoot入门案例
提示：springBoot建议在maven的模式下开发
springBoot集成了我们spring的系列产品，所以我们导包只需要导入一个springBoot就可以了

<project xmlnsprojectxmlns="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>com.lhc.springbootjpa</groupId>   <artifactId>SpringBoot_jpa_test1</artifactId>    <version>0.0.1-SNAPSHOT</version>    <parent>     <groupId>org.springframework.boot</groupId>     <artifactId>spring-boot-starter-parent</artifactId>     <version>1.5.2.RELEASE</version>  </parent>    <dependencies>      <dependency>        <groupId>junit</groupId>        <artifactId>junit</artifactId>        <version>3.8.1</version>        <scope>test</scope>      </dependency>      <dependency>         <groupId>org.springframework.boot</groupId>         <artifactId>spring-boot-starter-web</artifactId>      </dependency>      <!-- Spring boot 引用Thymeleaf模板依赖包（Thymeleaf模板如果不适用，这里也可以不添加这段配置，Thymeleaf模板使用在下面会讲到） -->  <dependency>             <groupId>org.springframework.boot</groupId>             <artifactId>spring-boot-starter-thymeleaf</artifactId>  </dependency>    </dependencies>  </project> 

编写Application类
1、新建项目的包结构

注意：【我们在com.xingxue下面新建Application类，这样就相当于springBoot默认扫描Application类所在所有包】
在resources下新建application.properties文件，里面是服务器的配置，比如修改端口号

package com.xingxue;

import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;@SpringBootApplication@Controller@RequestMapping("/test")public class Application {    public static void main(String[] args) {        SpringApplication.run(Application.class);    }    @RequestMapping("test.do")    public String test() {        System.out.println("1111111111111");        return "ok";    }}

直接右键以java程序运行即可，结果如下：

  .   ____          _            __ _ _ /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/  ___)| |_)| | | | | || (_| |  ) ) ) )  '  |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot ::        (v1.5.2.RELEASE)2017-12-07 14:40:54.337  INFO 4136 --- [           main] com.xingxue.Application                  : Starting Application on PC-20170521BQHB with PID 4136 (D:\wp_heyi2\SpringBoot\target\classes started by Administrator in D:\wp_heyi2\SpringBoot)2017-12-07 14:40:54.339  INFO 4136 --- [           main] com.xingxue.Application                  : No active profile set, falling back to default profiles: default2017-12-07 14:40:54.616  INFO 4136 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@1b853a5: startup date [Thu Dec 07 14:40:54 CST 2017]; root of context hierarchy2017-12-07 14:40:55.678  INFO 4136 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8089 (http)2017-12-07 14:40:55.689  INFO 4136 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat2017-12-07 14:40:55.690  INFO 4136 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.112017-12-07 14:40:55.818  INFO 4136 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext2017-12-07 14:40:55.818  INFO 4136 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1203 ms2017-12-07 14:40:55.939  INFO 4136 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]2017-12-07 14:40:55.944  INFO 4136 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]2017-12-07 14:40:55.945  INFO 4136 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]2017-12-07 14:40:55.949  INFO 4136 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]2017-12-07 14:40:55.950  INFO 4136 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]2017-12-07 14:40:56.264  INFO 4136 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@1b853a5: startup date [Thu Dec 07 14:40:54 CST 2017]; root of context hierarchy2017-12-07 14:40:56.321  INFO 4136 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/test/test.do]}" onto public java.lang.String com.xingxue.Application.test()2017-12-07 14:40:56.324  INFO 4136 --- [           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)2017-12-07 14:40:56.324  INFO 4136 --- [           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)2017-12-07 14:40:56.347  INFO 4136 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-12-07 14:40:56.347  INFO 4136 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-12-07 14:40:56.392  INFO 4136 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-12-07 14:40:56.418  WARN 4136 --- [           main] .t.AbstractTemplateResolverConfiguration : Cannot find template location: classpath:/templates/ (please add some templates or check your Thymeleaf configuration)2017-12-07 14:40:56.843  INFO 4136 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup2017-12-07 14:40:56.889  INFO 4136 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8089 (http)2017-12-07 14:40:56.895  INFO 4136 --- [           main] com.xingxue.Application                  : Started Application in 2.839 seconds (JVM running for 3.092)

输入地址 http://localhost:8080/test/test.do
我们发现控制台打印 如下

这时表明springboot已经运行，这个过程是：
首先springboot自带tomcat，当我们启动的时候，springboot就把该项目自动发布到自带的tomcat下面，然后默认使用8080端口启动tomcat，项目就已经发布成功，
我们访问的时候直接根据原来的方式访问即可，这时发现请求到达了controller，而我们注解实际上是使用springMVC注解，
总结一句话，相当于我们使用了springBoot，springBoot就默认帮我们生成了springMVC和spring的配置文件，而且自动帮我们发布项目