参考资料：MybatisPlus官网

创建数据库

CREATE DATABASE `mybatisplus`
​
USE `mybatisplus`
​
CREATE TABLE `user`(
id BIGINT(20) NOT NULL COMMENT '主键ID',
NAME VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
age INT(11) NULL DEFAULT NULL COMMENT '年龄',
email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',
PRIMARY KEY (id)
);
​
DELETE FROM USER;
​
INSERT INTO USER (id, NAME, age, email) VALUES
(1, 'Jone', 18, 'test1@baomidou.com'),
(2, 'Jack', 20, 'test2@baomidou.com'),
(3, 'Tom', 28, 'test3@baomidou.com'),
(4, 'Sandy', 21, 'test4@baomidou.com'),
(5, 'Billie', 24, 'test5@baomidou.com');

数据库名为 mybatisplus，表名为 user

创建一个springboot项目，一个web依赖即可

导入相关maven依赖

mysql

mysql mysql-connector-java

Lombok(不是必须品，只是可以偷点懒)

org.projectlombok lombok 1.18.12 true

mybatis-plus

com.baomidou mybatis-plus-boot-starter 3.0.5

配置application.properties

# mysql
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/mybatisplus?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8
# 东8时区，serverTimezone=GMT%2B8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
​
# 配置日志,方便查看SQL语句
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

实体类Pojo

User

package com.zy.pojo;
​
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
​
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
​
private Long id;
private String name;
private Integer age;
private String email;
​
}

mapper接口

　　实现 BaseMapper 接口

UserMapper

package com.zy.mapper;
​
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.zy.pojo.User;
import org.springframework.stereotype.Repository;
​
@Repository //代表持久层
​
//在对应的mapper上面 继承 基本的接口BaseMapper
public interface UserMapper extends BaseMapper {
//继承之后，所有的CRUD就完成了
​
}

主启动类扫描mapper

package com.zy;
​
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
​
//扫描mapper文件夹
@MapperScan("com.zy.mapper")
​
@SpringBootApplication
public class DemoApplication {
​
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
​
}

测试查找全部用户

@Test
public void select(){
​
//查询全部用户
List users = userMapper.selectList(null);
users.forEach(System.out::println);
​
}

结果