mybatis-plus提供支持ActiveRecord模式

mybatis-plus提供支持ActiveRecord模式

 

  在Mybatis-Plus中提供了ActiveRecord的模式，支持 ActiveRecord 形式调用，实体类只需继承 Model 类即可实现基本 CRUD 操作，简单来说就是一个实体类继承Model类，并通过注解与数据库的表名进行关联，这样就可以通过实体类直接进行表的简单增删改查操作，这样也确实极大的方便了开发人员。

 

原理理解：

       简单来说Mybatis-plus是基于Mybatis的基础之上进行开发的，其基本操作还是一个Mapper操作中对应一条sql语句，通过参数和返回值来处理sql语句的执行结果。那样我们可以理解Mybatis-Plus的ActiveRecord其实就是Mybatis-Plus给我们提供一些简单的增删改查操作SQl语句的自动生成操作，在Mybatis提供的BaseMapper中默认提供了一些简单增删改查操作，其通过自动生成sql来初始化Mybatis的一些操作，其最终实现和我们直接基于Mybatis开发是一致的。

 

具体实现：

实体继承Model类，以及加上@EqualsAndHashCode(callSuper = false)注解，不调用父类euqals和hashCode方法；

@Data
@EqualsAndHashCode(callSuper = false)
public class Department extends Model<Department>

CRUD demo案例：

package com.java1234;
 
 
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.java1234.entity.Department;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
 
import java.util.List;
 
 
/**
 * @author java1234_小锋
 * @site www.java1234.com
 * @company Java知识分享网
 * @create 2020-08-22 17:07
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class ActiveRecordTest {
 
 
    @Test
    public void insert(){
        Department department=new Department();
        department.setName("xx部门");
        department.setRemark("xxx");
        boolean insert = department.insert();
        System.out.println(insert);
    }
 
    @Test
    public void updateById(){
        Department department=new Department();
        department.setId(7);
        department.setName("xx部门2");
        department.setRemark("xxx2");
        boolean b = department.updateById();
        System.out.println(b);
    }
 
    @Test
    public void insertOrUpdate(){
        Department department=new Department();
        department.setId(8);
        department.setName("xx部门2");
        department.setRemark("xxx2");
        boolean b = department.insertOrUpdate();
        System.out.println(b);
    }
 
    @Test
    public void deleteById(){
        Department department=new Department();
        department.setId(7);
        boolean b = department.deleteById();
        System.out.println(b);
    }
 
    @Test
    public void selectById(){
        Department department=new Department();
        //Department d = department.selectById(1);  // 方式一
        department.setId(1);  // 方式二
        Department d = department.selectById();
        System.out.println(d);
    }
 
    @Test
    public void selectAll(){
        Department department=new Department();
        List<Department> departmentList = department.selectAll();
        System.out.println(departmentList);
    }
 
    @Test
    public void selectListByQueryMapper(){
        QueryWrapper<Department> queryWrapper=new QueryWrapper();
        // QueryWrapper<Employee> queryWrapper2=Wrappers.<Employee>query();
        queryWrapper.like("name","测试");
        Department department=new Department();
        List<Department> departmentList = department.selectList(queryWrapper);
        System.out.println(departmentList);
    }
 
 
 
}

 

 

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作者： java1234_小锋

出处：https://www.cnblogs.com/java688/p/13672107.html

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