在Spring 中使用@Aspect 控制自定义注解的操作

Spring 中使用@Aspect 控制自定义注解

看这篇介绍@Aspect

1.定义系统日志注解类

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface SysLog {
String value() default "";
}

2.定义切面处理类

package com.kxs.common.aspect;
import com.google.gson.Gson;
import com.kxs.common.annotation.SysLog;
import com.kxs.common.utils.HttpContextUtils;
import com.kxs.common.utils.IPUtils;
import com.kxs.modules.sys.entity.SysLogEntity;
import com.kxs.modules.sys.entity.SysUserEntity;
import com.kxs.modules.sys.service.SysLogService;
import org.apache.shiro.SecurityUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.util.Date;
/**
 * 系统日志，切面处理类
 * 
 * @author 
 * @email 
 * @date 
 */
@Aspect
@Component
public class SysLogAspect {
 @Autowired
 private SysLogService sysLogService;
 @Pointcut("@annotation(com.kxs.common.annotation.SysLog)")//指向自定义注解路径
 public void logPointCut() { 
 }
 /**
  * 切面记录系统日志
  * @param point
  * @return
  * @throws Throwable
  */
 @Around("logPointCut()")//
 public Object around(ProceedingJoinPoint point) throws Throwable {
  long beginTime = System.currentTimeMillis();
  //执行方法
  Object result = point.proceed();
  //执行时长(毫秒)
  long time = System.currentTimeMillis() - beginTime;
  //保存日志
  saveSysLog(point, time);
  return result;
 }
//保存日志
 private void saveSysLog(ProceedingJoinPoint joinPoint, long time) {
  MethodSignature signature = (MethodSignature) joinPoint.getSignature();
  Method method = signature.getMethod();
  SysLogEntity sysLog = new SysLogEntity();
  SysLog syslog = method.getAnnotation(SysLog.class);
  if(syslog != null){
   //注解上的描述
   sysLog.setOperation(syslog.value());
  }
  //请求的方法名
  String className = joinPoint.getTarget().getClass().getName();
  String methodName = signature.getName();
  sysLog.setMethod(className + "." + methodName + "()");
  //请求的参数
  Object[] args = joinPoint.getArgs();
  try{
   String params = new Gson().toJson(args[0]);
   sysLog.setParams(params);
  }catch (Exception e){
  }
  //获取request
  HttpServletRequest request = HttpContextUtils.getHttpServletRequest();
  //设置IP地址
  sysLog.setIp(IPUtils.getIpAddr(request));
  //用户名
  String username = ((SysUserEntity) SecurityUtils.getSubject().getPrincipal()).getUsername();
  sysLog.setUsername(username);
  sysLog.setTime(time);
  sysLog.setCreateDate(new Date());
  //保存系统日志
  sysLogService.save(sysLog);
 }
}

补充：为什么添加了@Aspect 还要加@Component

官方文档中有写：

You may register aspect classes as regular beans in your Spring XML configuration, or autodetect them through classpath scanning - just like any other Spring-managed bean. However, note that the @Aspect annotation is not sufficient for autodetection in the classpath: For that purpose, you need to add a separate @Component annotation (or alternatively a custom stereotype annotation that qualifies, as per the rules of Spring's component scanner).

翻译：

您可以在Spring XML配置中注册aspect类，或者通过类路径扫描自动检测它们，就像任何其他Spring管理bean一样。但是，请注意，@aspect注释对于在类路径中自动检测是不够的：为了达到这个目的，您需要添加一个单独的@component注解（或者根据Spring的组件扫描器的规则来定义一个定制的原型注解）。

以上为个人经验，希望能给大家一个参考，也希望大家多多支持小牛知识库。如有错误或未考虑完全的地方，望不吝赐教。