2、Mybatis-Plus 测试增、删、改、查

文章目录

• ​​1、数据库脚本​​

• ​​1.1 创建表​​
• ​​1.2 添加数据​​

• ​​2、创建实体类（使用lombok）​​
• ​​3、添加mapper​​

• ​​3.1 添加mapper​​
• ​​3.2 项目的目录结构​​

• ​​4、测试增删改查​​
• ​​5、测试结果​​

1、数据库脚本

1.1 创建表

CREATE DATABASE `mybatis_plus` /*!40100 DEFAULT CHARACTER SET utf8mb4 */;
 use `mybatis_plus`;
 CREATE TABLE `user` ( 
 `id` bigint(20) NOT NULL COMMENT '主键ID',
 `name` varchar(30) DEFAULT NULL COMMENT '姓名',
 `age` int(11) DEFAULT NULL COMMENT '年龄', 
 `email` varchar(50) DEFAULT NULL COMMENT '邮箱',
  PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;      

1.2 添加数据

INSERT INTO user (id, name, age, email) VALUES 
(1, 'Jone', 18, '[email protected]'), 
(2, 'Jack', 20, '[email protected]'), 
(3, 'Tom', 28, '[email protected]'), 
(4, 'Sandy', 21, '[email protected]'), 
(5, 'Billie', 24, '[email protected]');      

2、创建实体类（使用lombok）

public class User {

    private Long id;

    private String name;

    private Integer age;

    private String email;

}      

3、添加mapper

3.1 添加mapper

友情提示：管理哪个实体就写哪个实体

@Repository
public interface UserMapper extends BaseMapper<User> {

}      

3.2 项目的目录结构

4、测试增删改查

@SpringBootTest
public class MyBatisPlusTest {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelectList() {

        List<User> list = userMapper.selectList(null);
        list.forEach(System.out::println);

    }

//    测试增加
    @Test
    public void testAdd(){
        //实现用户新增
        //INSERT INTO user ( id, name, age, email ) VALUES ( ?, ?, ?, ? )

        User user = new User();
        user.setName("张三");
        user.setAge(23);
        user.setEmail("[email protected]");
        int rs = userMapper.insert(user);
        System.out.println("测试结果："+rs);
        System.out.println(user.getId());
    }

    @Test
    public void testDelete(){
        /**
         *  1、根据id删除信息
         *    DELETE FROM user WHERE id=?
         */
//        int rs = userMapper.deleteById(1531552463440584706L);
//        System.out.println(rs);

        /**
         * 2、根据map集合中所设置的条件删除用户信息
         * DELETE FROM user WHERE name = ? AND age = ?
         */
//        HashMap<String, Object> map = new HashMap<>();
//        map.put("name","张三");
//        map.put("age",23);
//        int rs = userMapper.deleteByMap(map);
//        System.out.println(rs);

        /**
         *  通过多个id实现批量删除
         *  DELETE FROM user WHERE id IN ( ? , ? , ? )
         */
        List<Long> list = Arrays.asList(1L,2L,3L);
        int rs = userMapper.deleteBatchIds(list);
        System.out.println(rs);

    }

    @Test
    public void testUpdate(){
        /**
         * 修改用户信息
         * UPDATE user SET name=?, email=? WHERE id=?
         */
        User user = new User();
        user.setId(4L);
        user.setName("李四");
        user.setEmail("[email protected]");
        int rs = userMapper.updateById(user);
        System.out.println(rs);
    }

    @Test
    public void testSelect(){
        /**
         * 通过id查询用户信息
         * SELECT id,name,age,email FROM user WHERE id=?
         */
//        User user = userMapper.selectById(4L);
//        System.out.println(user);

        /**
         * 根据id批量查询用户信息
         * SELECT id,name,age,email FROM user WHERE id IN ( ? , ? )
         */
//        List<Long> list = Arrays.asList(4L,5L);
//        List<User> users = userMapper.selectBatchIds(list);
//        users.forEach(System.out::println);

        /**
         * 根据条件查询用户信息
         * SELECT id,name,age,email FROM user WHERE name = ? AND age = ?
         */
//       Map<String,Object> map = new HashMap<>();
//       map.put("name","李四");
//       map.put("age",21);
//       List<User> users = userMapper.selectByMap(map);
//       users.forEach(System.out::println);

        //自定义sql语句查询用户信息
        Map<String,Object> map = userMapper.selectMapById(1L);
        System.out.println(map);
    }



}      

5、测试结果