建一个springboot项目

1.打开 https://start.spring.io/ 新建一个maven的demo,这里选择的是1.5.18的版本

2.将自动生成的demo导入eclipse，直接选中File里的import，注意导入的要是maven project

3.导入成功后mydemo的结构

4.测试一下我们的springboot项目

①添加web依赖，pom.xml文件如下

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.18.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>mydemo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mydemo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

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

        
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

②添加测试类TestMydemo，注意此类或者以后要添加的类都要和MydemoApplication.java在同一包，或者在它的子包，方便扫描

在同一包

在它的子包

package com.example.mydemo;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestMydemo {
    @RequestMapping("/hello")
    public String hello(){
        return "Hello Word!mydemo test";
    }   
}

③运行MydemoApplication.java：Run as -->Java Application

④访问：http://localhost:8080/hello