Spring AOP:将目标传递给Aspect [英] Spring AOP: passing target to Aspect

问题描述

我想捕获实现 Processor 接口的类抛出的异常.在一方面，我需要访问处理器，这将引发异常.我定义以下切入点:

I want to catch exceptions thrown by classes implementing Processor interface. In aspect I need an access to processor, which throws the exception. I define following pointcut:

@Pointcut("target(some.package.Processor) && args(message)")
  public void processor(Message message) {
}

和方面:

@AfterThrowing(pointcut="processor(message)", throwing="ex")
public void onExceptionInProcessor(Processor target, Exception ex, Message message) {
  // code skipped
}

但是，我遇到以下异常:

However, I get following exception:

Caused by: java.lang.IllegalArgumentException: error at ::0 formal unbound in pointcut 
    at org.aspectj.weaver.tools.PointcutParser.parsePointcutExpression(PointcutParser.java:301) ~[aspectjweaver-1.6.12.jar:1.6.12]
    at org.springframework.aop.aspectj.AspectJExpressionPointcut.buildPointcutExpression(AspectJExpressionPointcut.java:207) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.aspectj.AspectJExpressionPointcut.buildPointcutExpression(AspectJExpressionPointcut.java:193) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.aspectj.AspectJExpressionPointcut.checkReadyToMatch(AspectJExpressionPointcut.java:182) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.aspectj.AspectJExpressionPointcut.getClassFilter(AspectJExpressionPointcut.java:163) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.support.AopUtils.canApply(AopUtils.java:209) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.support.AopUtils.canApply(AopUtils.java:263) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.support.AopUtils.findAdvisorsThatCanApply(AopUtils.java:295) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.findAdvisorsThatCanApply(AbstractAdvisorAutoProxyCreator.java:117) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.findEligibleAdvisors(AbstractAdvisorAutoProxyCreator.java:87) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.getAdvicesAndAdvisorsForBean(AbstractAdvisorAutoProxyCreator.java:68) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.wrapIfNecessary(AbstractAutoProxyCreator.java:359) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessAfterInitialization(AbstractAutoProxyCreator.java:322) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) ~[spring-beans-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1461) ~[spring-beans-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) ~[spring-beans-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    ... 58 common frames omitted

将 target 对象绑定到方面的正确方法是什么?我发现的唯一方法是绑定 JoinPoint ，但建议如下:

What is a correct way of binding target object to aspect? The only way I've found is binding JoinPoint, but it suggests following:

除非您特别需要这种反射式访问，否则应使用 目标切入点指示符可以到达此对象以获得更好的静态效果 打字和表现

Unless you specifically need this reflective access, you should use the target pointcut designator to get at this object for better static typing and performance

有人能做到这一点吗?

推荐答案

您的target应引用方法中的参数名称之一.例如说

Your target should refer to one of the parameter names in the method. For example saying

@Pointcut("target(myProc) && args(message)")
public void processor(Processor myProc, Message message) {
}

将在myProc变量中以安全的方式为您提供Processor.

will give you the Processor in type safe way in myProc variable.

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