1：方法一：当下面使用到的字段值为空的时候，会根据提交自动填充进去

package com.hdx.contractor.util.mybatis;

import com.hdx.contractor.common.user.SecurityUser;
import com.hdx.contractor.common.user.UserDetail;
import com.hdx.contractor.util.query.oConvertUtils;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.binding.MapperMethod.ParamMap;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.*;
import org.springframework.stereotype.Component;

import java.lang.reflect.Field;
import java.util.Date;
import java.util.Properties;

/**
 * mybatis拦截器，自动注入创建人、创建时间、修改人、修改时间
 * @Author: xu
 * @Date: 2024-10-06
 * @Version: V1.0
 *
 */
@Slf4j
@Component
@Intercepts({ @Signature(type = Executor.class, method = "update", args = { MappedStatement.class, Object.class }) })
public class MybatisInterceptor implements Interceptor {



	@Override
	public Object intercept(Invocation invocation) throws Throwable {
		MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
		String sqlId = mappedStatement.getId();
		log.debug("------sqlId------" + sqlId);
		SqlCommandType sqlCommandType = mappedStatement.getSqlCommandType();
		Object parameter = invocation.getArgs()[1];
		log.debug("------sqlCommandType------" + sqlCommandType);

		if (parameter == null) {
			return invocation.proceed();
		}
		if (SqlCommandType.INSERT == sqlCommandType) {
			UserDetail sysUser = this.getLoginUser();
			Field[] fields = oConvertUtils.getAllFields(parameter);
			for (Field field : fields) {
				log.debug("------field.name------" + field.getName());
				try {
					if ("createBy".equals(field.getName())) {
						field.setAccessible(true);
						Object localCreateBy = field.get(parameter);
						field.setAccessible(false);
						if (localCreateBy == null || "".equals(localCreateBy)) {
							if (sysUser != null) {
								// 登录人账号
								field.setAccessible(true);
								field.set(parameter, sysUser.getUsername());
								field.setAccessible(false);
							}
						}
					}
					if ("userId".equals(field.getName())) {
						field.setAccessible(true);
						Object localuserId = field.get(parameter);
						field.setAccessible(false);
						if (localuserId == null || "".equals(localuserId)) {
							if (sysUser != null) {
								// 登录人账号
								field.setAccessible(true);
								field.set(parameter, sysUser.getId());
								field.setAccessible(false);
							}
						}
					}
					// 注入创建时间
					if ("createTime".equals(field.getName())) {
						field.setAccessible(true);
						Object localCreateDate = field.get(parameter);
						field.setAccessible(false);
						if (localCreateDate == null || "".equals(localCreateDate)) {
							field.setAccessible(true);
							field.set(parameter, new Date());
							field.setAccessible(false);
						}
					}

				} catch (Exception e) {
				}
			}
		}
		if (SqlCommandType.UPDATE == sqlCommandType) {
			UserDetail sysUser = this.getLoginUser();
			Field[] fields = null;
			if (parameter instanceof ParamMap) {
				ParamMap<?> p = (ParamMap<?>) parameter;
                String et = "et";
				if (p.containsKey(et)) {
					parameter = p.get(et);
				} else {
					parameter = p.get("param1");
				}

				if (parameter == null) {
					return invocation.proceed();
				}

				fields = oConvertUtils.getAllFields(parameter);
			} else {
				fields = oConvertUtils.getAllFields(parameter);
			}

			for (Field field : fields) {
				log.debug("------field.name------" + field.getName());
				try {
					if ("updateBy".equals(field.getName())) {
						//获取登录用户信息
						if (sysUser != null) {
							// 登录账号
							field.setAccessible(true);
							field.set(parameter, sysUser.getUsername());
							field.setAccessible(false);
						}
					}
					if ("updateTime".equals(field.getName())) {
						field.setAccessible(true);
						field.set(parameter, new Date());
						field.setAccessible(false);
					}
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
		return invocation.proceed();
	}

	@Override
	public Object plugin(Object target) {
		return Plugin.wrap(target, this);
	}

	@Override
	public void setProperties(Properties properties) {
		// TODO Auto-generated method stub
	}

    /**
     * 获取登录用户
     * @return
     */
	private UserDetail getLoginUser() {
		UserDetail sysUser = null;
		try {
			sysUser = SecurityUser.getUser();
		} catch (Exception e) {
			sysUser = null;
		}
		return sysUser;
	}

}

2：方法二：使用mybatis-plus自带注解@TableField自动填充

2-1：实体类对象如下，插入和更新添加响应的参数

    /**
     * 用户id
     */
    @TableField(fill = FieldFill.INSERT)
    private String user_Id;

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

2-2：实现mybatisplus的接口MetaObjectHandler

package io.hdx.admin.common.handler;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import io.hdx.admin.common.user.SecurityUser;
import io.hdx.admin.common.user.UserDetail;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;

/**
 * 公共字段，自动填充值
 *
 * @author xu
 * @Date: 2024-10-06
 * @Version: V1.0
 */
@Component
public class FieldMetaObjectHandler implements MetaObjectHandler {
    private final static String USER_ID = "userId";
    private final static String UPDATE_DATE = "updateDate";

    @Override
    public void insertFill(MetaObject metaObject) {
        UserDetail user = SecurityUser.getUser();
        if (user != null) {
            //用户id
            strictInsertFill(metaObject, USER_ID, String.class, Long.parseLong(user.getId()));

        }

    }

    @Override
    public void updateFill(MetaObject metaObject) {
        if (SecurityUser.getUser() != null) {
            //更新时间
            strictUpdateFill(metaObject, UPDATE_DATE, LocalDateTime.class, LocalDateTime.now());
        }
    }
}