java/mybatis-plus使用

MyBatis-PLUS（简称MP）是一个MyBatis的的增强工具，在MyBatis的的基础上只做增强不做改变，为简化开发，提高效率而生。

官网 https://baomidou.com/

1、新增mybatis-plus依赖

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.0</version>
        </dependency>

2、application.properties配置数据库链接

spring.application.name=demo
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.name=badianboke.com
spring.datasource.url=jdbc:mysql://localhost:3306/badianboke.com?serverTimezone=UTC
spring.datasource.username=badianboke.com
spring.datasource.password=badianboke.com

3、新建UserEntity实体类

package com.example.demo.entity;
import lombok.Data;
@Data
public class User {
    private Long id; //数据库bigint 20
    private String name;
    private Integer age;
}

4、新建UserMapper接口

package com.example.demo.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.entity.User;
import org.springframework.stereotype.Repository;

@Repository
public interface UserMapper extends BaseMapper<User> {
}

5、启动类扫描mapper

package com.example.demo;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("com.example.demo.mapper")
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

6、新建测试

     @Test
    public void testSelect() {
        List<User> list = userMapper.selectList(null);
        System.out.println(list);
    }

    @Test
    public void testAdd() {
        User user = new User();
       // user.setId(100L);
        user.setAge(210);
        user.setName("aa");
        userMapper.insert(user);
    }

    @Test
    public void testUpdate() {
        User user = new User();
        user.setId(100L);
        user.setAge(210);
        user.setName("aabb");

        userMapper.updateById(user);
    }