Implementation of Mybatis Plus Automatic Filling and Update Operation Related Fields

Directory Scenario Introduction Autofill processor Mybatis-Plus configuration class Configure auto-population policies for related fields in entity classes

It is stated in the table building protocol of Ali Development Manual that there should be create_time and update_time fields in the database table; Then, in the development, the processing of these common fields should be unified, which can simplify our development process. Then this article records the automatic field filling in Mybatis-Plus.

Scene introduction

In the data table design of the project, each table has four fields: create_id, create_time, update_id and update_time, so in the application of Java, these four fields should be changed accordingly for the addition and modification operations:

create_id , update_id To automatically populate ID as the currently logged-in user create_time , update_time To automatically populate as the current time

Let's talk about the code implementation:

Autofill processor

The MetaObjectHandler interface in Mybatis-Plus needs to be implemented

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import hw.topevery.basis.runtime.UserRuntime;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.util.Objects;

/**
 *  Update related field handler 
 *
 * @author whw
 * @date 2020/1/3 16:41
 */
@Component
public class UpdateRelatedFieldsMetaHandler implements MetaObjectHandler {

    /**
     *  Add operation 
     *
     * @param metaObject
     */
    @Override
    public void insertFill(MetaObject metaObject) {
        this.strictInsertFill(metaObject, "createId", String.class, getCurrentUserId());
        this.strictInsertFill(metaObject, "createTime", LocalDateTime.class, LocalDateTime.now());
        this.strictInsertFill(metaObject, "updateId", String.class, getCurrentUserId());
        this.strictInsertFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
    }

    /**
     *  Update operation 
     *
     * @param metaObject
     */
    @Override
    public void updateFill(MetaObject metaObject) {
        this.strictUpdateFill(metaObject, "updateId", String.class, getCurrentUserId());
        this.strictUpdateFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
    }

    /**
     *  Get the current logged-in user ID
     *
     * @return
     */
    private String getCurrentUserId() {
        return " Current Login User ID";
    }
}

Mybatis-Plus configuration class

The processor needs to be injected into the Spring container to take effect

import com.baomidou.mybatisplus.core.config.GlobalConfig;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import hw.topevery.kunming.wapi.handler.UpdateRelatedFieldsMetaHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * Mybatis-Plus Configuration class 
 *
 * @author whw
 * @date 2020/1/3 16:41
 */
@Configuration
public class MybatisPlusConfig {

    @Bean
    public GlobalConfig globalConfig() {
        GlobalConfig globalConfig = new GlobalConfig();
        globalConfig.setMetaObjectHandler(new UpdateRelatedFieldsMetaHandler());
        return globalConfig;
    }
}

Configure auto-population policies for related fields in entity classes

Setting the fill property in the @ TableField annotation

Field Fill Policy FieldFill Description

值	描述
DEFAULT	默认不处理
INSERT	插入填充字段
UPDATE	更新填充字段
INSERT_UPDATE	插入和更新填充字段

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

import java.io.Serializable;
import java.time.LocalDateTime;

/**
 *  Basic entity class 
 *
 * @author whw
 * @date 2020/1/3 17:37
 */
@Data
public class BaseEntity implements Serializable {

    private static final long serialVersionUID = 1L;

    @ApiModelProperty(value = " Create a user ID")
    @TableField(value = "c_create_id", fill = FieldFill.INSERT)
    private String createId;

    @ApiModelProperty(value = " Creation time ")
    @TableField(value = "c_create_time", fill = FieldFill.INSERT)
    private LocalDateTime createTime;

    @ApiModelProperty(value = " Update users ID")
    @TableField(value = "c_update_id", fill = FieldFill.INSERT_UPDATE)
    private String updateId;

    @ApiModelProperty(value = " Update time ")
    @TableField(value = "c_update_time", fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;
}

Here, I extracted a parent class from the entity. Of course, I can also add annotations to the corresponding fields of the entity class directly.