MyBatis-Plus自动填充字段的详细教程

<dependencies>
    <!-- MyBatis-Plus -->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.5.1</version>
    </dependency>

    <!-- 其他必要依赖 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- MySQL 驱动 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
</dependencies>

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/your_database?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
    username: your_username
    password: your_password
    driver-class-name: com.mysql.cj.jdbc.Driver

mybatis-plus:
  mapper-locations: classpath:/mapper/*.xml
  type-aliases-package: com.example.entity
  global-config:
    db-config:
      id-type: auto

package com.example.utils;

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import lombok.Data;

import java.io.Serializable;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Data
public class BaseEntity implements Serializable {

    private static final long serialVersionUID = 1L;

    /**
     * 搜索值（暂时忽略）
     */
    @JsonIgnore
    @TableField(exist = false)
    private String searchValue;

    /**
     * 创建者
     */
    @TableField(fill = FieldFill.INSERT)
    private String createBy;

    /**
     * 创建时间
     */
    @TableField(fill = FieldFill.INSERT)
    private Date createTime;

    /**
     * 更新者
     */
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private String updateBy;

    /**
     * 更新时间
     */
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Date updateTime;

    /**
     * 请求参数（暂时忽略）
     */
    @JsonInclude(JsonInclude.Include.NON_EMPTY)
    @TableField(exist = false)
    private Map<String, Object> params = new HashMap<>();

}

package com.example.config;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.util.Date;

@Component
public class MyMetaObjectHandler implements MetaObjectHandler {

    @Override
    public void insertFill(MetaObject metaObject) {
        // 填充创建时间和更新时间
        this.strictInsertFill(metaObject, "createTime", Date.class, new Date());
        this.strictInsertFill(metaObject, "updateTime", Date.class, new Date());
        // 可以根据业务需求获取当前用户，填充创建者和更新者
        this.strictInsertFill(metaObject, "createBy", String.class, getCurrentUser());
        this.strictInsertFill(metaObject, "updateBy", String.class, getCurrentUser());
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        // 更新时只填充更新时间和更新者
        this.strictUpdateFill(metaObject, "updateTime", Date.class, new Date());
        this.strictUpdateFill(metaObject, "updateBy", String.class, getCurrentUser());
    }

    // 示例方法：获取当前用户信息
    private String getCurrentUser() {
        // 这里可以集成 Spring Security 或其他上下文获取实际的当前用户
        return "system"; // 这是一个占位符，实际应用中会替换为真实用户信息
    }
}

package com.example.entity;

import com.baomidou.mybatisplus.annotation.TableName;
import com.example.utils.BaseEntity;
import lombok.Data;

@Data
@TableName("your_table")
public class YourEntity extends BaseEntity {
    // 其他字段
    private String name;
    private Integer age;
}

@Service
public class YourEntityService {

    @Autowired
    private YourEntityMapper yourEntityMapper;

    public void saveEntity(YourEntity entity) {
        yourEntityMapper.insert(entity);
    }

    public void updateEntity(YourEntity entity) {
        yourEntityMapper.updateById(entity);
    }
}

spring:
  jackson:
    date-format: yyyy-MM-dd HH:mm:ss
    time-zone: GMT+8