spring boot入门

1 eclipse新建Maven工程，选择quickstart archetype
2 POM.xml中引入相关依赖

<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>com.rrfare</groupId>
  <artifactId>springboot</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>
  <name>springboot</name>
  <url>http://maven.apache.org</url>
  <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  </properties>
  <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>
  </dependencies>
</project>

3 建立spring boot启动类

@ComponentScan(value = {"com.rrfare.controller"})  //
@EnableAutoConfiguration  
public class App {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(App.class, args);
    }
}

4 新建controller

package com.rrfare.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {


     @Value("${username}")
     private String username;

     @Value("${password}")
     private String password;

     @Value("${company}")
     private String company;

    @RequestMapping("/user")
    public String getUserInfo(){
        return this.username + "\n" + this.password  + "\n" + this.company;
    }
}

5 在src/main/resources新建application.properties，注意名称不能随意取

username=liup
password=xxxxxxx
company=gooagoo

6 执行pom.xml，clean spring-boot:run

7 Spring boot优势
（1）不用配置web.xml
（2）不用配置spring/springmvc配置文件了
（3）不用安装tomcat，spring boot内嵌Tomcat

8 相关名词解释
（1）spring-boot-starter-parent：提供spring boot工程基础maven配置
（2）spring-boot-starter-web：添加Tomcat and Spring MVC功能
（3）@EnableAutoConfiguration：根据pom.xml中引入jar自动判断工程类型并进行相应配置，例如dependency中引入spring-boot-starter-web，则判断该工程为web工程（即使在工程建立时选择quick start archetype 而不是 web archetype）
（4）@RestController：返回方法return内容，相当于@ResponseBody+@Controller
注意1：使用@RestController无法返回jsp（配置的视图解析器InternalResourceViewResolver不起作用），只有@Controller才行
注意2：如果需要返回JSON，XML或自定义mediaType内容到页面，则需要在对应的方法上加上@ResponseBody注解