5.Java Spring框架源码分析-AOP-目标方法是怎么执行的

目录

1. 继续放行断点执行Calc.div

2. 进入到代理对象的intercept方法

  • CglibAopProxy.DynamicAdvisedInterceptor#intercept
public Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
	Object oldProxy = null;
	boolean setProxyContext = false;
	Class<?> targetClass = null;
	Object target = null;
	try {
		if (this.advised.exposeProxy) {
			// Make invocation available if necessary.
			oldProxy = AopContext.setCurrentProxy(proxy);
			setProxyContext = true;
		}
		//获取目标类
		target = getTarget();
		if (target != null) {
			targetClass = target.getClass();
		}
		//获取拦截器链
		List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);
		Object retVal;
		// Check whether we only have one InvokerInterceptor: that is,
		// no real advice, but just reflective invocation of the target.
		if (chain.isEmpty() && Modifier.isPublic(method.getModifiers())) {
			// We can skip creating a MethodInvocation: just invoke the target directly.
			// Note that the final invoker must be an InvokerInterceptor, so we know
			// it does nothing but a reflective operation on the target, and no hot
			// swapping or fancy proxying.
			Object[] argsToUse = AopProxyUtils.adaptArgumentsIfNecessary(method, args);
			retVal = methodProxy.invoke(target, argsToUse);
		}
		else {
			// 有拦截器链，那么封装成CglibMethodInvocation调用proceed方法
			retVal = new CglibMethodInvocation(proxy, target, method, args, targetClass, chain, methodProxy).proceed();
		}
		//没有拦截器链，直接执行目标方法
		retVal = processReturnType(proxy, target, method, retVal);
		return retVal;
	}
	finally {
		if (target != null) {
			releaseTarget(target);
		}
		if (setProxyContext) {
			// Restore old proxy.
			AopContext.setCurrentProxy(oldProxy);
		}
	}
}

2.1. 获取拦截器链

  • AdvisedSupport#getInterceptorsAndDynamicInterceptionAdvice
public List<Object> getInterceptorsAndDynamicInterceptionAdvice(Method method, Class<?> targetClass) {
	MethodCacheKey cacheKey = new MethodCacheKey(method);
	List<Object> cached = this.methodCache.get(cacheKey);
	if (cached == null) {
		//获取所有的增强器，一个默认的，其他四个我们的
		cached = this.advisorChainFactory.getInterceptorsAndDynamicInterceptionAdvice(
				this, method, targetClass);
		this.methodCache.put(cacheKey, cached);
	}
	return cached;
}

2.1.1. 将增强器转换成Inteceptor

  • DefaultAdvisorChainFactory#getInterceptorsAndDynamicInterceptionAdvice
public List<Object> getInterceptorsAndDynamicInterceptionAdvice(
		Advised config, Method method, Class<?> targetClass) {
	//遍历所有的增强器，转换成Inteceptor
	// This is somewhat tricky... We have to process introductions first,
	// but we need to preserve order in the ultimate list.
	List<Object> interceptorList = new ArrayList<Object>(config.getAdvisors().length);
	Class<?> actualClass = (targetClass != null ? targetClass : method.getDeclaringClass());
	boolean hasIntroductions = hasMatchingIntroductions(config, actualClass);
	AdvisorAdapterRegistry registry = GlobalAdvisorAdapterRegistry.getInstance();

	for (Advisor advisor : config.getAdvisors()) {
		if (advisor instanceof PointcutAdvisor) {
			// Add it conditionally.
			PointcutAdvisor pointcutAdvisor = (PointcutAdvisor) advisor;
			if (config.isPreFiltered() || pointcutAdvisor.getPointcut().getClassFilter().matches(actualClass)) {
				MethodMatcher mm = pointcutAdvisor.getPointcut().getMethodMatcher();
				if (MethodMatchers.matches(mm, method, actualClass, hasIntroductions)) {
					MethodInterceptor[] interceptors = registry.getInterceptors(advisor);
					if (mm.isRuntime()) {
						// Creating a new object instance in the getInterceptors() method
						// isn't a problem as we normally cache  
						for (MethodInterceptor interceptor : interceptors) {
							interceptorList.add(new InterceptorAndDynamicMethodMatcher(interceptor, mm));
						}
					}
					else {
						interceptorList.addAll(Arrays.asList(interceptors));
					}
				}
			}
		}
		else if (advisor instanceof IntroductionAdvisor) {
			IntroductionAdvisor ia = (IntroductionAdvisor) advisor;
			if (config.isPreFiltered() || ia.getClassFilter().matches(actualClass)) {
				Interceptor[] interceptors = registry.getInterceptors(advisor);
				interceptorList.addAll(Arrays.asList(interceptors));
			}
		}
		else {
			Interceptor[] interceptors = registry.getInterceptors(advisor);
			interceptorList.addAll(Arrays.asList(interceptors));
		}
	}

	return interceptorList;
}

2.2. 有拦截器则执行拦截器和目标方法

  • ReflectiveMethodInvocation#proceed
public Object proceed() throws Throwable {
	//	We start with an index of -1 and increment early.
	//currentInterceptorIndex表示执行到第几个拦截器，从-1开始
	//interceptorsAndDynamicMethodMatchers表示所有拦截器
	//如果没有拦截器的话那么执行invokeJoinpoint--即目标方法
	//或者所有的拦截器都执行完了，那么执行invokeJoinpoint--即目标方法
	if (this.currentInterceptorIndex == this.interceptorsAndDynamicMethodMatchers.size() - 1) {
		return invokeJoinpoint();
	}

	//执行第0个
	Object interceptorOrInterceptionAdvice =
			this.interceptorsAndDynamicMethodMatchers.get(++this.currentInterceptorIndex);
	if (interceptorOrInterceptionAdvice instanceof InterceptorAndDynamicMethodMatcher) {
		// Evaluate dynamic method matcher here: static part will already have
		// been evaluated and found to match.
		InterceptorAndDynamicMethodMatcher dm =
				(InterceptorAndDynamicMethodMatcher) interceptorOrInterceptionAdvice;
		if (dm.methodMatcher.matches(this.method, this.targetClass, this.arguments)) {
			return dm.interceptor.invoke(this);
		}
		else {
			// Dynamic matching failed.
			// Skip this interceptor and invoke the next in the chain.
			return proceed();
		}
	}
	else {
		// It's an interceptor, so we just invoke it: The pointcut will have
		// been evaluated statically before this object was constructed.
		//接着走到这里
		return ((MethodInterceptor) interceptorOrInterceptionAdvice).invoke(this);
	}
}
  • org.springframework.aop.interceptor.ExposeInvocationInterceptor#invoke
public Object invoke(MethodInvocation mi) throws Throwable {
	MethodInvocation oldInvocation = invocation.get();
	invocation.set(mi);
	try {
		//又开始执行上面的org.springframework.aop.framework.ReflectiveMethodInvocation#proceed
		//就是递归
		return mi.proceed();
	}
	finally {
		invocation.set(oldInvocation);
	}
}

2.2.1. 最后的流程是这样执行的

ExposeInvocationInterceptor（6）
AspectJAfterThrowingAdvice（5）
AfterReturningAdviceInterceptor（4）
AspectJAfterAdvice（3）
MethodBeforeAdviceInterceptor（1）
目标方法（2）
posted @ 2025-07-04 10:40  ThinkerQAQ  阅读(10)  评论(0)    收藏  举报