In MyBatis-Plus, org.apache.ibatis.binding.BindingException occurs.

Jun 10, 2024#异常 #MyBatis338

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AI-generated summary

The issue was with the selectById method not being able to find the primary key in the User entity class. The solution was to specify the primary key in the User entity class using @TableId annotation.

I have searched through various GPT and CSDN articles, but have not found the correct solution. It is commonly said that the issue is 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
}