Spring Boot入门第一天：Hello, Spring Boot!

1. 新建一个Maven Web项目。

2. 配置pom.xml文件。

<?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>com.yws710.springboot</groupId>
    <artifactId>demo1</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

3. 编写控制器类

package com.yws710.springboot.demo1.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * Created by Administrator on 2017/7/19.
 */
@Controller
public class HelloController {

    @ResponseBody
    @RequestMapping("/hello")
    public String hello() {
        return "Hello, Spring Boot!";
    }
}

4. 编写启动类

package com.yws710.springboot.demo1;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * Created by Administrator on 2017/7/19.
 */
@SpringBootApplication
public class App {

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

}

5. 启动项目。只需要运行上面代码的main方法，运行成功，控制台输出如下：

"D:\Program Files\Java\jdk1.7.0_67\bin\java" ...

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.4.RELEASE)

省略部分信息
2017-07-20 00:16:44.849  INFO 5388 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-07-20 00:16:44.858  INFO 5388 --- [           main] com.yws710.springboot.demo1.App          : Started App in 5.835 seconds (JVM running for 6.364)

6. 在浏览器中输入 http://localhost:8080/hello，显示结果如下：

好了，一个最简单的Web项目完成了。没有写任何的配置文件，也没有任何的xml文件（这里完全可以把web.xml文件删掉）。