Hello_SpringBoot_demo

一：用idea 创建 springboot 项目：

详情请参考：《使用IDEA创建一个springboot项目》

二：具体代码内容

1：StartAppLication

package com.alancode.springboot;

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

/**
 * @program: Hello_springBoot-demo1
 * @description: StartAppLication  项目启动器
 * <p>
 * 注意：
 * 关于编写启动器需要注意的问题。
 * 启动器存放位置：启动器可以和controller 位于同一个包 package下，或者位于controller的上一级包。
 * 但是不能把该文件放到controller平行级的包或者其子包下。
 * @author: Alan_Liu
 * @create: 2021-02-14 21:47
 */
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class StartAppLication {
	/**
	 * 调用 springboot 启动
	 *
	 * @return
	 * @throws
	 * @Param: [args]
	 * @author Alan_Liu
	 * @date 2021/2/14 22:16
	 **/
	public static void main(String[] args) {
		/***
		 *
		 *
		 *@Param: [args]
		 *@return
		 *@throws
		 *@author Alan_Liu
		 *@date 2021/2/14 22:23
		 *
		 **/
		SpringApplication.run(StartAppLication.class, args);
	}

}

2：HelloWorld

package com.alancode.springboot.controller;

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

import java.util.HashMap;
import java.util.Map;

/**
 * @program: Hello_springBoot-demo1
 * @description: HelloWorld
 * @author: Alan_Liu
 * @create: 2021-02-14 21:47
 */
@Controller
public class HelloWorld {

	/**
	 * @return
	 * @throws
	 * @Param: []
	 * @author Alan_Liu
	 * @date 2021/2/14 21:52
	 **/
	@RequestMapping("/hello")
	@ResponseBody
	public Map<String, Object> showHelloWolrd() {
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("msg", "HelloWorld");
		return map;
	}


}

3：pom.xml

<?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 https://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>2.4.2</version>
        <relativePath/>   <!-- lookup parent from repository -->
    </parent>
    <groupId>com.AlanCode.springBoot</groupId>
    <artifactId>demo1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo1</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <!--設置 jdk版本-->
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--注入 springboot启动器
          所谓springboot 启动器 其实就是 一些jar包的集合。springboot 一共提供了44款启动器
          1：spring-boot-starter-web:
              支持全栈式的web开发，包括 tomcat  springmvc 等jar.
          2:spring-boot-starter-jdbc
               支持spring以jdbc方式操作数据库的jar包的集合。
          3：spring-boot-starter-redis

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

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

</project>

4：启动StartAppLication