1. 实体类

原则：继承Model

package com.gblfy.springboot.mybatisplus.entity;import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableName;
import com.baomidou.mybatisplus.extension.activerecord.Model;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;import java.time.LocalDateTime;@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@TableName("user")
public class User  extends Model<User> {private Long id;private String name;private Integer age;private String email;//数据库没有此字段 只为了封装演示@TableField(exist = false)private String remark;
}

2. 实战

package com.gblfy.springboot.mybatisplus.mapper;import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.conditions.update.LambdaUpdateChainWrapper;
import com.gblfy.springboot.mybatisplus.entity.User;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
@Slf4j
public class UserARTest {@Testpublic void insertAR(){User user = new User();user.setName("刘华");user.setAge(20);user.setEmail("test@gblfy.com");boolean insert = user.insert();System.out.println(insert);}@Testpublic void selectByIdAR(){User user = new User();User user1 = user.selectById(111L);System.out.println(user == user1);System.out.println(user1);}@Testpublic void selectByIdAR2(){User user = new User();user.setId(11L);User user1 = user.selectById();System.out.println(user == user1);System.out.println(user1);}@Testpublic void updateByIdAR(){User user = new User();user.setId(11L);user.setName("你的纳斯达克");boolean user1 = user.updateById();System.out.println(user1);}@Testpublic void delByIdAR(){User user = new User();user.setId(11L);boolean user1 = user.deleteById();System.out.println(user1);}
}