Public field automatic filling in Mybatis Plus

This article mainly introduces the relevant information of SpringBoot Mybatis Plus public field automatic filling function. Friends who need it can refer to it

1. Application scenarios

Usually when building an object table, there will be two fields: last modification time and last modification person. For these fields that most tables have, these must be taken into consideration every time when adding or modifying. It's very troublesome to know whether several fields have been passed in. mybatisPlus has a great solution. That is the function of automatic filling of public fields. Generally, this function can be used for fields that meet the following conditions:

This field is found in most tables.

The value of this field is fixed, or the field value can be obtained dynamically in the background.

The two fields commonly used are last_update_time and last_update_name.

2. Configure MybatisPlus

Guide package: The only thing to note is that mybatisPlus is only supported in version 2.0.6Update Data public fields are automatically filled in. Previously, they could only be used when adding new data.

If you are a student who has configured MybatisPlus before, you only need to add the following steps:

Inherit IMetaObjectHandlerAbstract class, implement insertFill() new There are two methods: field settings that need to be filled when adding data and field settings that need to be filled when updateFill() updates data:

package io.z77z.util;
import java.util.Date;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.shiro.SecurityUtils;
import org.springframework.stereotype.Component;
import com.baomidou.mybatisplus.mapper.MetaObjectHandler;
import io.z77z.entity.SysUser;
/** mybatisplus自定义填充公共字段 ,即没有传的字段自动填充*/
@Component
public class MyMetaObjectHandler extends MetaObjectHandler {
  //新增填充
  @Override
  public void insertFill(MetaObject metaObject) {
    Object lastUpdateNameId = metaObject.getValue("lastUpdateNameId");
    Object lastUpdateTime = metaObject.getValue("lastUpdateTime");
    //获取当前登录用户
    SysUser user = (SysUser)SecurityUtils.getSubject().getPrincipal();
    if (null == lastUpdateNameId) {
      metaObject.setValue("lastUpdateNameId", user.getId());
    }
    if (null == lastUpdateTime) {
      metaObject.setValue("lastUpdateTime", new Date());
    }
  }
  //更新填充
  @Override
  public void updateFill(MetaObject metaObject) {
    insertFill(metaObject);
  }
}

Note: The parameters of the getValue() method are variables in the pojo class (Camel case naming method).

In the configuration file of mybatisplus, the bean of the public field generation class:

// MP 全局配置，更多内容进入类看注释
GlobalConfiguration globalConfig = new GlobalConfiguration();
//配置公共字段自动填写
globalConfig.setMetaObjectHandler(new MyMetaObjectHandler());

is the setting to fill in the public field just written to the MP global configuration object.

Filled fields need to ignore validation, add the following annotation on the corresponding attribute of the table object pojo class:

/**
 * 最后修改人Id
 */
@TableField(value="last_update_id",validate=FieldStrategy.NOT_EMPTY)
private String lastUpdateNameId;
/**
 * 最后修改时间
 */
@TableField(value="last_update_time",validate=FieldStrategy.NOT_EMPTY)
private Date lastUpdateTime;

Reason: Because when the update and insert methods are called, It will verify whether the attribute you passed is empty to determine whether this attribute should be updated and inserted. This conflicts with the automatic filling of public fields, so this annotation is needed to identify that this attribute does not require verification. Otherwise, the filling will fail during insertion.

3. Writing test classes

//公共字段自动填充
//1.在mybatisplus的配置文件中公共字段生成类的bean
//2.实现IMetaObjectHandler类
//3.忽略对应字段的为空检测，在pojo类的属性上添加@TableField(value="last_update_name_id",validate=FieldStrategy.IGNORED)
@Test
public void publicTest(){
  SysUser user = new SysUser();
  user.setEmail("1093615728@qq.com");
  user.setNickname("z77z");
  user.setPswd("123123");
  user.setStatus("1");
  sysUserService.insert(user);
  sysUserService.selectById(user.getId());
  SysUser user1 = new SysUser();
  user1.setPswd("123");
  user1.setId(user.getId());
  sysUserService.updateById(user1);
  sysUserService.selectById(user.getId());
}

4. Test log

2017/04/23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.insert- ==> Preparing: INSERT INTO sys_user (id, nickname, email, pswd, `status`,last_update_name_id , last_update_time ) VALUES ( ?, ?, ?, ?, ?,?, ? )
2017/04/23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.insert- ==> ; Parameters: 6634923de4a14b6ca3bac5fdf31563a8(String), z77z(String), 1093615728@qq.com(String), 123123(String), 1(String), 123(String), 2017-04-23 19:35:26.58(Time stamp)
2017/04/23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.insert- <== Updates: 1
2017/04/23-19:35:26 [ main] DEBUG io.z77z.dao.SysUserMapper.selectById- ==> createTime FROM sys_user WHERE id=?
2017/04/23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.selectById- ==> Parameters: 6634923de4a14b6ca3bac5fdf31563a8(String)
2017/ 04/23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.selectById- <==  Total: 1
2017/04/23-19:35:26 [main] DEBUG io. z77z.dao.SysUserMapper.updateById- ==> Preparing: UPDATE sys_user SET pswd=?, last_update_name_id=?, last_update_time=? WHERE id=?
2017/04/23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.updateById- ==> /04 /23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.updateById- <== Updates: 1
2017/04/23-19:35:26 [main] DEBUG io.z77z .dao.SysUserMapper.selectById- ==> Preparing: SELECT id,nickname,email,pswd,last_login_time AS lastLoginTime,`status`,last_update_name_id AS lastUpdateNameId,create_name_id AS createNameId,last_update_time AS lastUpdateTime,create_time AS createTime FROM sys_user WHERE id= ?
2017/04/23-19:35:26 [main] DEBUG io.z77z.dao.SysUserMapper.selectById- ==> Parameters: 6634923de4a14b6ca3bac5fdf31563a8(String)
2017/04/23-19: 35:26 [main] DEBUG io.z77z.dao.SysUserMapper.selectById- <== Total: 1

##5. Summary

It was originally planned to use this method to process the creator and creation time. Finally, it was found that if these two fields are also ignored as empty, that is, validate=FieldStrategy.NOT_EMPTY is added when updating the data. The creator and creation time will be updated together. Otherwise, it will be updated to empty. So I think the public field autofill function of mybatisPlus is good, but it is not perfect when used for real needs.

【Related recommendations】

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3. Alibaba Java Development Manual

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