Spring AOP + 自定义注解 实现公共字段的填充

代码冗,不利于后期维护.

定义操作这些字段的方法类型

实现步骤：

• 自定义注解AutoFill,用于表示操作这些公共字段的方法
• 自定义切面类AutoFillAspect,统一拦截，通过反射获取方法入参，并填充公共字段
• 在Mapper的insert、update的方法上加上自定义的AutoFill注解

代码：

- 不使用mybatis-plus自带的填充注解

必要依赖

 <dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.8.7</version>
</dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.1.0</version>
</dependency>
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.11</version>
</dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId><version>2.7.5</version>
</dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.18</version>
</dependency>

1、自定义注解AutoFill,用于表示操作这些公共字段的方法

import com.cwh.mpdemo.enums.OpreaType;import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;/*** 自定义注解，表示方法*/
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface AutoFill {/*** 操作类型** @return*/OpreaType value() default OpreaType.INSERT;
}

2、自定义切面类AutoFillAspect,统一拦截，通过反射获取方法入参，并填充公共字段

import com.cwh.mpdemo.annotation.AutoFill;
import com.cwh.mpdemo.enums.OpreaType;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.Date;/*** @Aspect 标注为切面类*/
@Aspect
@Component
@Slf4j
public class AutoFillaspect {// 定义切点@Pointcut("execution(* com.cwh.mpdemo.mapper.*.*(..)) && @annotation(com.cwh.mpdemo.annotation.AutoFill)")public void pointcut(){}// 定义通知@Before("pointcut()")public void before(JoinPoint joinPoint){log.info("auto fill start...");MethodSignature signature = (MethodSignature) joinPoint.getSignature();AutoFill annotation = signature.getMethod().getAnnotation(AutoFill.class);OpreaType value = annotation.value();//获取签名方法的入参Object[] args = joinPoint.getArgs();if (args.length ==0 ||args == null)  {return;}Object arg = args[0];try {// 填充字段if (value == OpreaType.INSERT){//通过反射给入参对象的字段赋值arg.getClass().getDeclaredMethod("setCreateTime", Date.class).invoke(arg, Date.from(LocalDateTime.now().toInstant(ZoneOffset.UTC)));//实际中从ThreadLocal获取用户id          arg.getClass().getDeclaredMethod("setCreateUser",String.class).invoke(arg,"test");} arg.getClass(). getDeclaredMethod("setUpdateTime",Date.class).invoke(arg,Date.from(LocalDateTime.now().toInstant(ZoneOffset.UTC)));//实际中从ThreadLocal获取用户idarg.getClass().getDeclaredMethod("setUpdateUser",String.class).invoke(arg,"test");}catch (Exception exception){log.error("auto fill error:{}",exception.getMessage());}log.info("auto fill end...");}
}

public enum OpreaType {INSERT,UPDATE;
}

3、在Mapper的insert、update的方法上加上自定义的AutoFill注解

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.cwh.mpdemo.annotation.AutoFill;
import com.cwh.mpdemo.domain.SessionDomain;public interface SessionLoginMapper extends BaseMapper<SessionDomain> {@AutoFillvoid insertData(SessionDomain sessionDomain);
}

- 使用mybatis-plus自带的填充注解

首先在实体对象上加自动填充属性注解fill = FieldFill.INSERT

@Data
@TableName("session_login")
public class SessionDomain {@TableId(value = "id", type = IdType.AUTO)private Long id;@TableFieldprivate String userName;@TableField(fill = FieldFill.INSERT)private Date createTime;@TableField(fill = FieldFill.INSERT)private String createUser;@TableField(fill = FieldFill.UPDATE)private Date updateTime;@TableField(fill = FieldFill.UPDATE)private String updateUser;
}

实现元数据对象处理器接口MetaObjectHandler，实现insertFill,updateFill逻辑

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.Date;@Component
public class AutoFillHandler implements MetaObjectHandler {@Overridepublic void insertFill(MetaObject metaObject) {// 设置属性值this.setFieldValByName("createTime", Date.from(LocalDateTime.now().toInstant(ZoneOffset.UTC)), metaObject);this.setFieldValByName("updateTime", Date.from(LocalDateTime.now().toInstant(ZoneOffset.UTC)), metaObject);//实际中从ThreadLocal获取用户idthis.setFieldValByName("createUser", "1", metaObject);this.setFieldValByName("updateUser", "1", metaObject);}@Overridepublic void updateFill(MetaObject metaObject) {//实际中从ThreadLocal获取用户idthis.setFieldValByName("updateTime", Date.from(LocalDateTime.now().toInstant(ZoneOffset.UTC)), metaObject);this.setFieldValByName("updateUser", "1", metaObject);}
}	

剩下就是在service层使用mapper接口insert、update数据即可。