这里将会介绍怎么去搭建一个简单增删改查的Springboot项目，认真看完我相信你一定能够学会，并且附有完整代码；
目录
- 一、搭建数据库
- 1.建数据库
- 2.建表
- 二、新建IDEA项目
- 三、连接数据库
- 1.编写文件
- 2.连接MySQL
- 四、写代码
- pojo层
- mapper层
- Service层
- Controller层
- 写mapper层的映射文件
- 五、测试
- Apifox测试结果（没Apifox直接跳过）
- 网页测试
- 六、完整代码
- UserController
- UserMapper
- User
- UserService
- UserMapper.xml
- application.properties
- pom.xml
一、搭建数据库
首先要进行增删改查肯定是要有供操作的数据库；
这里我是用的SQLyog来搭建的，随便用什么都可以，只要能确保给项目一个配套的数据库就行；
1.建数据库
CREATE DATABASE springBoot;2.建表
CREATE TABLE USER(NAME VARCHAR(30),id INT(11),sex VARCHAR(10)) DEFAULT CHARSET=utf8二、新建IDEA项目
打开IDEA，创建一个新项目，准备开始动手
然后选择插件
点击创建
在pom.xml里导入Lombok依赖
org.projectlomboklombok然后搭建四层架构
controller，mapper，pojo，service
创建mapper的映射文件
三、连接数据库
1.编写文件
在resources包下找到application.properties，将如下代码写入：
spring.datasource.username=rootspring.datasource.password=adminspring.datasource.url=jdbc:mysql://localhost:3306/mybatis" /> 2.连接MySQL
选择我们之前建好的数据库
点击Apply和OK后，我们就可以看到我们连接了数据库
四、写代码
经过前面的准备工作后终于可以开始写代码了；
这里我就只介绍一个接口（查找所有用户），其他的都是差不多的流程，文章末尾附完整代码；
pojo层
实体类里的属性要与数据表一一对应；
mapper层
查询所有用户是要返回多个User，所以用List；
Service层
先用@Autowired注入userMapper；
然后声明方法；
Controller层
同样注入
然后调用Service层
写mapper层的映射文件
将查询的SQL语句写上
到此这个接口就算是写完了；
五、测试
我建议是拿Apifox来测试，自己拿网页测试也行；
先手动添加一些数据到数据库里去；
Apifox测试结果（没Apifox直接跳过）
网页测试
注：一定要先让项目保持运行状态
打开浏览器，访问接口路径：
http://localhost:8080/queryUserList
六、完整代码
UserController
package com.example.springboot.controller;import com.example.springboot.pojo.User;import com.example.springboot.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RestController;import java.util.List;@RestControllerpublic class UserController {@AutowiredUserService userService;@GetMapping ("/queryUserList")public List<User> queryUserList(){return userService.queryUserList();}@GetMapping ("queryUserById")public User queryUserById(int user_id){return userService.queryUserById(user_id);}@GetMapping("/addUser")public String addUser(User user){return userService.addUser(user);}@GetMapping("/deleteUserById")public String deleteUserById(int id){return userService.deleteUserById(id);}}
UserMapper
package com.example.springboot.mapper;import com.example.springboot.pojo.User;import org.apache.ibatis.annotations.Mapper;import org.springframework.stereotype.Repository;import java.util.List;@Mapper@Repositorypublic interface UserMapper {List<User> queryUserList();User queryUserById(int id);void addUser(User user);void deleteUserById(int id);}
User
package com.example.springboot.pojo;import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;@Data@NoArgsConstructor@AllArgsConstructorpublic class User {private String name;private int id;private String sex;}
UserService
package com.example.springboot.service;import com.example.springboot.mapper.UserMapper;import com.example.springboot.pojo.User;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import java.util.List;@Servicepublic class UserService {@AutowiredUserMapper userMapper;public List<User> queryUserList(){return userMapper.queryUserList();}public User queryUserById(int id){User user= userMapper.queryUserById(id);return user;}public String addUser(User user){userMapper.addUser(user);return "新增成功";}public String deleteUserById(int id){userMapper.deleteUserById(id);return "删除成功";}}
UserMapper.xml
<" />="1.0" encoding="UTF-8" ?><!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.example.springboot.mapper.UserMapper"><select id="queryUserList" resultType="User">select * from springboot.user</select><select id="queryUserById" resultType="User" parameterType="int">select * from springboot.user where id = #{id};</select><insert id="addUser">insert into springboot.user (name, id, sex) VALUES (#{name},#{id},#{sex})</insert><delete id="deleteUserById">delete from springboot.user where id=#{id}</delete></mapper>
application.properties
spring.datasource.username=rootspring.datasource.password=adminspring.datasource.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver#??mybatismybatis.type-aliases-package=com.example.springboot.pojomybatis.mapper-locations=classpath:mybatis/mapper/*.xmlserver.port=8080
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><groupId>com.example</groupId><artifactId>springBoot</artifactId><version>0.0.1-SNAPSHOT</version><name>springBoot</name><description>springBoot</description><properties><java.version>1.8</java.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><spring-boot.version>2.6.13</spring-boot.version></properties><dependencies><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.1.1</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>com.mysql</groupId><artifactId>mysql-connector-j</artifactId><scope>runtime</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies><dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>${spring-boot.version}</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><build><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.8.1</version><configuration><source>1.8</source><target>1.8</target><encoding>UTF-8</encoding></configuration></plugin><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>${spring-boot.version}</version><configuration><mainClass>com.example.springboot.Application</mainClass><skip>true</skip></configuration><executions><execution><id>repackage</id><goals><goal>repackage</goal></goals></execution></executions></plugin></plugins></build></project>