The tinyint of mybatis notes is automatically converted to boolean

background

Data table definition

create table timed_task (
    id                  bigint unsigned auto_increment comment 'PK' primary key,
    task_status         tinyint(1) default 0                 not null comment '任务状态：1启用，2禁用',
    mq_switch           tinyint(1) default 0                 not null comment '是否发送消息至MQ：1发送，0不发送',
    isactive 			tinyint(1) default 1 				 not null comment '逻辑删除',
    inserttime          datetime   default CURRENT_TIMESTAMP not null comment '插入时间',
	insertby            varchar(100)                         null comment '创建人',
    updatetime          datetime   default CURRENT_TIMESTAMP not null on update CURRENT_TIMESTAMP comment '更新时间',
    updateby            varchar(100)                         null comment '更新人'
) comment '定时任务配置表' collate = utf8mb4_unicode_ci;

There are three tinyintfields.
The Java interface is defined as:

List<Map> selectListBySelective(Map<String, Object> map);

Mybatis mapper file definition:

<select id="selectListBySelective" parameterType="Map" resultType="Map">
    select
    tt.id,
    ifnull(tt.task_status, 0) as taskStatus,
    tt.mq_switch as mqSwitch,
    tt.inserttime,
    tt.insertby,
    date_format(tt.updatetime,'%Y-%m-%d %H:%i:%s') as updatetime,
    tt.updateby,
    ifnull(tt.isactive, 0)
    from timed_task tt
    where tt.isactive = 1
    order by tt.updatetime desc
</select>

It can be seen that tinyintthe processing methods for the three different fields are different.
For Spring Boot + mybatis reasons, a application.propertiesnew configuration information is added to the configuration file : logging.level.com.aaa.mapper=debugyou can print and output SQL statements to the log console.
The SQL statement is as follows:

select tt.id,
       ifnull(tt.task_status, 0)                       as taskStatus,
       tt.mq_switch                                    as mqSwitch,
       tt.inserttime,
       tt.insertby,
       date_format(tt.updatetime, '%Y-%m-%d %H:%i:%s') as updatetime,
       tt.updateby,
       ifnull(tt.isactive, 0)
from ppdai_feiyu.timed_task tt
where tt.isactive = 1
order by tt.updatetime desc

Get the SQL statement to DataGrip to execute, there is no problem:

id	taskStatus	mqSwitch	inserttime	insertby	updatetime	updateby	ifnull(tt.isactive, 0)
3	1	1	2020-08-26 10:49:52	awesome	2020-08-26 10:49:52	awesome	1

But the return data obtained by postman calling the interface is:

{
    
    
  "list": [
    {
    
    
      "id": 3,
      "ifnull(tt": {
    
    
        "isactive, 0)": 1
      },
      "inserttime": "1598410192000",
      "mqSwitch": true,
      "taskStatus": 1,
      "updateby": "awesome",
      "insertby": "awesome",      
      "updatetime": "2020-08-26 10:49:52",
    }
  ]
}

analysis

Question 1

The inserttime field is of the datetime type, and the value becomes timestamp, unless date_format(tt.updatetime, '%Y-%m-%d %H:%i:%s') as updatetimeit is handled as the same.

Question 1

When the return value is Map type (ie resultType="Map"), the data of the tinyint(1)type in the data table (ie [1, 0]) will be automatically converted into boolean type data (ie [true/false]) by mybatis . Refer to the tinyint(1) data in Mybatis to automatically convert the data to boolean for processing .
solution:

1. Use to ifnull(column, 0)process the field
2. Add parameters in jdbcUrl: tinyInt1isBit=false(default is true)
3. Avoid using tinyint type fields with a length of 1 to store data in numeric format.

In the author's problem scenario, only the first solution is recommended. That is, through ifnull processing. Therefore, you can see that it taskStatusreturns 1 as expected, but mqSwitchstill returns true.

Question 2

isactiveFields are also used ifnull(tt.isactive, 0)加以处理, but there is no subsequent asexpression part. The interface return is actually:

"ifnull(tt": {
    
    
  "isactive, 0)": 1
},

Remarks

The mybatis used in this article is mybatis-spring-boot-starter, version:

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.0.1</version>
    <!--升级到这个版本，还是有问题-->
    <!--<version>2.1.3</version>-->
</dependency>

Corresponding mybatis version:

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.5.1</version>
    <!--<version>3.5.5</version>-->
</dependency>

reference

The tinyint(1) data in Mybatis is automatically converted to boolean processing