MyBatis Plus实现时间字段自动填充的完整方案

/**
 * 邮箱服务器实体类
 */
@Entity
@Table(name = "tbl_email_server")
public class EmailServer extends BaseEntity {
    
    // 其他字段...
    
    /** 创建时间 */
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @TableField(fill = FieldFill.INSERT)
    private Date createTime;

    /** 更新时间 */
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @TableField(fill = FieldFill.INSERT_UPDATE)  
    private Date updateTime;
    
    // getter 和 setter 方法...
}

package com.ruoyi.framework.config;

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

import java.util.Date;

/**
 * MyBatis Plus 字段自动填充处理器
 * 
 * @author ruoyi
 */
@Component
public class MyBatisMetaObjectHandler implements MetaObjectHandler {

    /**
     * 插入时的填充策略
     */
    @Override
    public void insertFill(MetaObject metaObject) {
        Date now = new Date();
        
        // 插入时同时填充创建时间和更新时间
        this.strictInsertFill(metaObject, "createTime", Date.class, now);
        this.strictInsertFill(metaObject, "updateTime", Date.class, now);
    }

    /**
     * 更新时的填充策略  
     */
    @Override
    public void updateFill(MetaObject metaObject) {
        // 更新时仅填充更新时间
        this.strictUpdateFill(metaObject, "updateTime", Date.class, new Date());
    }
}

@Override
public int insertEmailServer(EmailServer emailServer) {
    // 手动设置时间字段
    emailServer.setCreateBy(SecurityUtils.getUsername());
    emailServer.setCreateTime(new Date());  // ❌ 需要移除
    emailServer.setUpdateTime(new Date());  // ❌ 需要移除
    return emailServerMapper.insertEmailServer(emailServer);
}

@Override
public int updateEmailServer(EmailServer emailServer) {
    emailServer.setUpdateBy(SecurityUtils.getUsername());
    emailServer.setUpdateTime(new Date());  // ❌ 需要移除  
    return emailServerMapper.updateEmailServer(emailServer);
}

@Override
public int insertEmailServer(EmailServer emailServer) {
    // 只设置创建者，时间字段由 MyBatis Plus 自动填充
    emailServer.setCreateBy(SecurityUtils.getUsername());
    return emailServerMapper.insertEmailServer(emailServer);
}

@Override
public int updateEmailServer(EmailServer emailServer) {
    // 只设置更新者，更新时间由 MyBatis Plus 自动填充
    emailServer.setUpdateBy(SecurityUtils.getUsername());
    return emailServerMapper.updateEmailServer(emailServer);
}

// 执行插入操作
EmailServer emailServer = new EmailServer();
emailServer.setServerName("SMTP服务器");
// ... 设置其他业务字段

// 调用 insertEmailServer 时，MyBatis Plus 会：
// 1. 触发 insertFill 方法
// 2. createTime = 2024-01-15 10:30:25  
// 3. updateTime = 2024-01-15 10:30:25 (与创建时间相同)

// 执行更新操作
EmailServer emailServer = new EmailServer();
emailServer.setServerId(1L);
emailServer.setServerName("新的服务器名称");
// ... 修改其他业务字段

// 调用 updateEmailServer 时，MyBatis Plus 会：
// 1. 触发 updateFill 方法
// 2. createTime = 保持原值不变
// 3. updateTime = 2024-01-15 14:25:30 (更新为当前时间)

-- 为时间字段添加默认值
ALTER TABLE tbl_email_server 
MODIFY COLUMN create_time datetime DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间';

ALTER TABLE tbl_email_server 
MODIFY COLUMN update_time datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间';

@Override
public void insertFill(MetaObject metaObject) {
    Date now = new Date();
    
    // 支持 Date 类型
    this.strictInsertFill(metaObject, "createTime", Date.class, now);
    this.strictInsertFill(metaObject, "updateTime", Date.class, now);
    
    // 支持 LocalDateTime 类型
    this.strictInsertFill(metaObject, "createTime", LocalDateTime.class, LocalDateTime.now());
    this.strictInsertFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
    
    // 支持时间戳
    this.strictInsertFill(metaObject, "createTime", Long.class, System.currentTimeMillis());
}

@Override
public void insertFill(MetaObject metaObject) {
    Date now = new Date();
    String currentUser = getCurrentUser(); // 获取当前用户
    
    // 时间字段填充
    this.strictInsertFill(metaObject, "createTime", Date.class, now);
    this.strictInsertFill(metaObject, "updateTime", Date.class, now);
    
    // 用户字段填充
    this.strictInsertFill(metaObject, "createBy", String.class, currentUser);
    this.strictInsertFill(metaObject, "updateBy", String.class, currentUser);
}

@Override  
public void updateFill(MetaObject metaObject) {
    String currentUser = getCurrentUser();
    
    this.strictUpdateFill(metaObject, "updateTime", Date.class, new Date());
    this.strictUpdateFill(metaObject, "updateBy", String.class, currentUser);
}

private String getCurrentUser() {
    try {
        return SecurityUtils.getUsername();
    } catch (Exception e) {
        return "system"; // 默认用户
    }
}

// 确保字段名正确映射
@TableField(value = "create_time", fill = FieldFill.INSERT)
private Date createTime;

// 确保处理器被 Spring 管理
@Component  // 必须添加此注解
public class MyBatisMetaObjectHandler implements MetaObjectHandler {
    // ...
}

// 使用 FieldFill.INSERT 而不是 INSERT_UPDATE
@TableField(fill = FieldFill.INSERT)  // ✅ 正确
private Date createTime;

@TableField(fill = FieldFill.INSERT_UPDATE)  // ✅ 正确
private Date updateTime;

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
@TableField(fill = FieldFill.INSERT_UPDATE)
private Date updateTime;