1.mybatisplus的作用

主要是解决java对象和数据库表和字段的映射关联

2.mybatisplus使用流程

2.1pom.xml文件中增加依赖（点击右上角蓝色按钮下载依赖）

注意修改你的spinrtboot版本为2.7.6,不同版本的依赖版本也是不一样的

以下代码供复制

<!--mybatisPlus依赖--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.2</version></dependency><!--mysql依赖驱动--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><!--数据库连接池druid--><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.1.20</version></dependency>

2.2navicat新建数据库，增加application.properties数据库配置

2.2.1 新建数据库，并建立一个user表

2.2.2application.properties文件增加内容

以下代码供复制

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mydb?useSSL=false
spring.datasource.username=root
spring.datasource.password=123456
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

2.3 启动类添加注解，增加mapper包操作数据库

2.3.1增加mapper包，并新建一个UserMapper接口interface操作用户表

UserMapper的内容

UserMapper内容供复制

package org.example.mybatisdemo.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;
import org.example.mybatisdemo.entity.User;@Mapper
public interface UserMapper extends BaseMapper<User> {}

2.3.2启动类增加注解，标识要扫描的mapper包

2.5添加实体类（类属性和建立的User表一致）

供参考代码

package org.example.mybatisdemo.entity;public class User {private int id;private String username;private String password;private String birth;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getBirth() {return birth;}public void setBirth(String birth) {this.birth = birth;}@Overridepublic String toString() {return "User{" +"id=" + id +", username='" + username + '\'' +", password='" + password + '\'' +", birth='" + birth + '\'' +'}';}
}

2.4添加控制器包，给前端提供接口

代码供复制

package org.example.mybatisdemo.controller;import org.example.mybatisdemo.entity.User;
import org.example.mybatisdemo.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.List;@RestController
public class UserController {@Autowiredprivate UserMapper userMapper;@GetMapping("/user")public String query() {List<User> list = userMapper.selectList(null);System.out.println(list);return list.toString();}@PostMapping("/user")public String save(User user) {int i = userMapper.insert(user);if (i > 0) {return "插入成功";} else {return "插入失败";}}}

3.浏览器访问测试

3.2浏览器测试

接口实现成功
3.2postman测试（插入成功）