MyBatis-Plus 中出現 org.apache.ibatis.binding.BindingException

I have searched various GPT and CSDN articles, but I haven't found the correct solution. It is commonly said that it is an issue with the XML file location...

Error code#

User class

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("user")
public class User {
    @TableField("user_id")
    private Long userId;       // User ID
    @TableField("user_name")
    private String userName;   // Username
    @TableField("user_password")
    private String userPassword; // User password
    @TableField("user_authority")
    private Integer userAuthority; // User authority
}

Mapper interface

@Mapper
public interface UserMapper extends BaseMapper<User> {

}

Test method

@SpringBootTest
public class UserTest {
    @Autowired
    private UserMapper userMapper;

    // Select user by id
    @Test
    public void testSelectById() {
        User user = userMapper.selectById(1);
        System.out.println(user);
    }
}

Solution and Reason#

Since the primary key is not specified in the User entity class, the selectById method cannot find the primary key.

Therefore, the solution is to add @TableId in the User entity class to specify the primary key @TableId(value = "user_id", type = IdType.AUTO)

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("user")
public class User {
    // Add it here
    @TableId(value = "user_id", type = IdType.AUTO)
    @TableField("user_id")
    private Long userId;       // User ID
  
    @TableField("user_name")
    private String userName;   // Username
    @TableField("user_password")
    private String userPassword; // User password
    @TableField("user_authority")
    private Integer userAuthority; // User authority
}