Spring AOP基于注解的“零配置”方式实现

Posted 2020-08-09

1. 为了在Spring中启动@AspectJ支持，需要在类加载路径下新增两个AspectJ库：aspectjweaver.jar和aspectjrt.jar。除此之外，Spring AOP还需要依赖一个aopalliance.jar包
2. 定义一个类似ServiceAspect.java这样的切面bean:

3.  1 package com.hyq.aop;
    2 
    3 import org.apache.commons.logging.Log;
    4 import org.apache.commons.logging.LogFactory;
    5 import org.aspectj.lang.JoinPoint;
    6 import org.aspectj.lang.ProceedingJoinPoint;
    7 import org.aspectj.lang.annotation.After;
    8 import org.aspectj.lang.annotation.AfterReturning;
    9 import org.aspectj.lang.annotation.AfterThrowing;
   10 import org.aspectj.lang.annotation.Around;
   11 import org.aspectj.lang.annotation.Aspect;
   12 import org.aspectj.lang.annotation.Before;
   13 import org.aspectj.lang.annotation.Pointcut;
   14 import org.springframework.stereotype.Component;
   15 
   16 /**
   17  * 系统服务组件Aspect切面Bean
   18  * @author Shenghany
   19  */
   20 //声明这是一个组件
   21 @Component
   22 //声明这是一个切面Bean
   23 @Aspect
   24 public class ServiceAspect {
   25 
   26     private final static Log log = LogFactory.getLog(ServiceAspect.class);
   27 
   28     //配置切入点,该方法无方法体,主要为方便同类中其他方法使用此处配置的切入点
   29     @Pointcut("execution(* com.hyq.aop..*(..))")
   30     public void aspect(){    }
   31 
   32     /*
   33      * 配置前置通知,使用在方法aspect()上注册的切入点
   34      * 同时接受JoinPoint切入点对象,可以没有该参数
   35      */
   36     @Before("aspect()")
   37     public void before(JoinPoint joinPoint){
   38         System.out.println("执行before.....");
   39     }
   40 
   41     //配置后置通知,使用在方法aspect()上注册的切入点
   42     @After("aspect()")
   43     public void after(JoinPoint joinPoint){
   44         System.out.println("执行after.....");
   45     }
   46 
   47     //配置环绕通知,使用在方法aspect()上注册的切入点
   48     @Around("aspect()")
   49     public void around(JoinPoint joinPoint){
   50         long start = System.currentTimeMillis();
   51         try {
   52             ((ProceedingJoinPoint) joinPoint).proceed();
   53             long end = System.currentTimeMillis();
   54             if(log.isInfoEnabled()){
   55                 log.info("around " + joinPoint + "\tUse time : " + (end - start) + " ms!");
   56             }
   57         } catch (Throwable e) {
   58             long end = System.currentTimeMillis();
   59             if(log.isInfoEnabled()){
   60                 log.info("around " + joinPoint + "\tUse time : " + (end - start) + " ms with exception : " + e.getMessage());
   61             }
   62         }
   63     }
   64 
   65     //配置后置返回通知,使用在方法aspect()上注册的切入点
   66     @AfterReturning("aspect()")
   67     public void afterReturn(JoinPoint joinPoint){
   68         if(log.isInfoEnabled()){
   69             log.info("afterReturn " + joinPoint);
   70         }
   71     }
   72 
   73     //配置抛出异常后通知,使用在方法aspect()上注册的切入点
   74     @AfterThrowing(pointcut="aspect()", throwing="ex")
   75     public void afterThrow(JoinPoint joinPoint, Exception ex){
   76         if(log.isInfoEnabled()){
   77             log.info("afterThrow " + joinPoint + "\t" + ex.getMessage());
   78         }
   79     }
   80 
   81 }

   3.定义一个业务组件，如：

4.  1 package com.hyq.aop;
    2 
    3 import org.apache.commons.logging.Log;
    4 import org.apache.commons.logging.LogFactory;
    5 import org.springframework.stereotype.Component;
    6 @Component()
    7 public class UserService {
    8 
    9     private final static Log log = LogFactory.getLog(UserService.class);
   10     
   11     public User get(long id){
   12         if(log.isInfoEnabled()){
   13             log.info("getUser method . . .");
   14         }
   15         return new User();
   16     }
   17     
   18     public void save(User user){
   19         if(log.isInfoEnabled()){
   20             log.info("saveUser method . . .");
   21         }
   22     }
   23     
   24     public boolean delete(long id) throws Exception{
   25         if(log.isInfoEnabled()){
   26             log.info("delete method . . .");
   27             throw new Exception("spring aop ThrowAdvice演示");
   28         }
   29         return false;
   30     }
   31     
   32 }

   业务组件要用@Component()注解修饰

　　　　4.在bean.xml中加入下面配置:

1 <!-- 激活组件扫描功能,在包com.hyq.aop及其子包下面自动扫描通过注解配置的组件 -->
2     <context:component-scan base-package="com.hyq.aop"/>
3     <!-- 激活自动代理功能 -->
4     <!-- <aop:aspectj-autoproxy proxy-target-class="true"/> -->
5     <aop:aspectj-autoproxy/>