public class SpringClientAop { public static void main(String[] args) { Resource resource = new ClassPathResource("applicationContext2.xml"); DefaultListableBeanFactory defaultListableBeanFactory = new DefaultListableBeanFactory(); BeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(defaultListableBeanFactory); beanDefinitionReader.loadBeanDefinitions(resource);
打印： befor MyAdvisor invoke! my method invoke after MyAdvisor invoke! class com.sun.proxy.$Proxy4 class java.lang.reflect.Proxy 4 com.tdl.spring.aop.service.MyService org.springframework.aop.SpringProxy org.springframework.aop.framework.Advised org.springframework.core.DecoratingProxy
AopProxy： Delegate interface for a configured AOP proxy, allowing for the creation of actual proxy objects. Out-of-the-box implementations are available for JDK dynamic proxies and for CGLIB proxies, as applied by DefaultAopProxyFactory。 针对于可配置的aop代理的接口，允许创建真实的代理对象。 开箱即用的DefaultAopProxyFactory实现有jdk的动态代理和cglib的代理。
// Don't let calling code try to dereference the factory if the bean isn't a factory. if (BeanFactoryUtils.isFactoryDereference(name)) { if (beanInstance instanceof NullBean) { return beanInstance; } if (!(beanInstance instanceof FactoryBean)) { throw new BeanIsNotAFactoryException(beanName, beanInstance.getClass()); } if (mbd != null) { mbd.isFactoryBean = true; } return beanInstance; }
// Now we have the bean instance, which may be a normal bean or a FactoryBean. // If it's a FactoryBean, we use it to create a bean instance, unless the // caller actually wants a reference to the factory. //判断创建出来的bean是不是FactoryBean if (!(beanInstance instanceof FactoryBean)) { return beanInstance; } //以下逻辑是FactoryBean的流程 Object object = null; if (mbd != null) { mbd.isFactoryBean = true; } else { //缓存可能得到为null object = getCachedObjectForFactoryBean(beanName); } if (object == null) { // Return bean instance from factory. //将ProxyFactoryBean转换为接口的类型 FactoryBean<?> factory = (FactoryBean<?>) beanInstance; // Caches object obtained from FactoryBean if it is a singleton. //判断bean的定义在缓存是否存在 if (mbd == null && containsBeanDefinition(beanName)) { mbd = getMergedLocalBeanDefinition(beanName); } boolean synthetic = (mbd != null && mbd.isSynthetic()); //从工厂bean返回代理对象 object = getObjectFromFactoryBean(factory, beanName, !synthetic); } return object; }
//factory：org.springframework.aop.framework.ProxyFactoryBean //beanName：myAop //shouldPostProcess: true protected Object getObjectFromFactoryBean(FactoryBean<?> factory, String beanName, boolean shouldPostProcess) { if (factory.isSingleton() && containsSingleton(beanName)) { synchronized (getSingletonMutex()) { Object object = this.factoryBeanObjectCache.get(beanName); if (object == null) { //真正工厂获取的动作 object = doGetObjectFromFactoryBean(factory, beanName); // Only post-process and store if not put there already during getObject() call above // (e.g. because of circular reference processing triggered by custom getBean calls) Object alreadyThere = this.factoryBeanObjectCache.get(beanName); if (alreadyThere != null) { object = alreadyThere; } else { if (shouldPostProcess) { if (isSingletonCurrentlyInCreation(beanName)) { // Temporarily return non-post-processed object, not storing it yet.. return object; } beforeSingletonCreation(beanName); try { object = postProcessObjectFromFactoryBean(object, beanName); } catch (Throwable ex) { throw new BeanCreationException(beanName, "Post-processing of FactoryBean's singleton object failed", ex); } finally { afterSingletonCreation(beanName); } } if (containsSingleton(beanName)) { this.factoryBeanObjectCache.put(beanName, object); } } } return object; } } else { Object object = doGetObjectFromFactoryBean(factory, beanName); if (shouldPostProcess) { try { object = postProcessObjectFromFactoryBean(object, beanName); } catch (Throwable ex) { throw new BeanCreationException(beanName, "Post-processing of FactoryBean's object failed", ex); } } return object; } }
// Do not accept a null value for a FactoryBean that's not fully // initialized yet: Many FactoryBeans just return null then. if (object == null) { if (isSingletonCurrentlyInCreation(beanName)) { throw new BeanCurrentlyInCreationException( beanName, "FactoryBean which is currently in creation returned null from getObject"); } object = new NullBean(); } return object; }
//获取对象 public Object getObject() throws BeansException { initializeAdvisorChain(); if (isSingleton()) { //返回代理对象的单例的实例 return getSingletonInstance(); } else { if (this.targetName == null) { logger.info("Using non-singleton proxies with singleton targets is often undesirable. " + "Enable prototype proxies by setting the 'targetName' property."); } return newPrototypeInstance(); } } //创建单例的实例 private synchronized Object getSingletonInstance() { if (this.singletonInstance == null) { //targetSource内部引用了com.tdl.spring.aop.service.impl.MyServiceImpl //即得到目标增强的目标对象 this.targetSource = freshTargetSource(); if (this.autodetectInterfaces && getProxiedInterfaces().length == 0 && !isProxyTargetClass()) { // Rely on AOP infrastructure to tell us what interfaces to proxy. Class<?> targetClass = getTargetClass(); if (targetClass == null) { throw new FactoryBeanNotInitializedException("Cannot determine target class for proxy"); } setInterfaces(ClassUtils.getAllInterfacesForClass(targetClass, this.proxyClassLoader)); } // Initialize the shared singleton instance. super.setFrozen(this.freezeProxy); //getProxy得到代理 //createAopProxy方法在org.springframework.aop.framework.ProxyCreatorSupport内部实现 this.singletonInstance = getProxy(createAopProxy()); } return this.singletonInstance; }
//初始化通知器链 private synchronized void initializeAdvisorChain() throws AopConfigException, BeansException { if (this.advisorChainInitialized) { return; } //检查interceptorNames（myAop配置了interceptorNames字符串数组） if (!ObjectUtils.isEmpty(this.interceptorNames)) { if (this.beanFactory == null) { throw new IllegalStateException("No BeanFactory available anymore (probably due to serialization) " + "- cannot resolve interceptor names " + Arrays.asList(this.interceptorNames)); }
// Globals can't be last unless we specified a targetSource using the property... if (this.interceptorNames[this.interceptorNames.length - 1].endsWith(GLOBAL_SUFFIX) && this.targetName == null && this.targetSource == EMPTY_TARGET_SOURCE) { throw new AopConfigException("Target required after globals"); }
// Materialize interceptor chain from bean names. for (String name : this.interceptorNames) { if (name.endsWith(GLOBAL_SUFFIX)) { if (!(this.beanFactory instanceof ListableBeanFactory)) { throw new AopConfigException( "Can only use global advisors or interceptors with a ListableBeanFactory"); } addGlobalAdvisors((ListableBeanFactory) this.beanFactory, name.substring(0, name.length() - GLOBAL_SUFFIX.length())); }
else { // If we get here, we need to add a named interceptor. // We must check if it's a singleton or prototype. Object advice; if (this.singleton || this.beanFactory.isSingleton(name)) { // Add the real Advisor/Advice to the chain. //从beanFactoy获取bean(beanFactory是DefaultListableBeanFactory) //这里又会执行getBean的流程。 //获取通知器/通知 advice = this.beanFactory.getBean(name); } else { // It's a prototype Advice or Advisor: replace with a prototype. // Avoid unnecessary creation of prototype bean just for advisor chain initialization. advice = new PrototypePlaceholderAdvisor(name); } //把Advisor添加到链表当中 addAdvisorOnChainCreation(advice); } } }
final class JdkDynamicAopProxy implements AopProxy, InvocationHandler, Serializable { public JdkDynamicAopProxy(AdvisedSupport config) throws AopConfigException { Assert.notNull(config, "AdvisedSupport must not be null"); if (config.getAdvisors().length == 0 && config.getTargetSource() == AdvisedSupport.EMPTY_TARGET_SOURCE) { throw new AopConfigException("No advisors and no TargetSource specified"); } this.advised = config; }
try { if (!this.equalsDefined && AopUtils.isEqualsMethod(method)) { // The target does not implement the equals(Object) method itself. return equals(args[0]); } else if (!this.hashCodeDefined && AopUtils.isHashCodeMethod(method)) { // The target does not implement the hashCode() method itself. return hashCode(); } else if (method.getDeclaringClass() == DecoratingProxy.class) { // There is only getDecoratedClass() declared -> dispatch to proxy config. return AopProxyUtils.ultimateTargetClass(this.advised); } else if (!this.advised.opaque && method.getDeclaringClass().isInterface() && method.getDeclaringClass().isAssignableFrom(Advised.class)) { // Service invocations on ProxyConfig with the proxy config... return AopUtils.invokeJoinpointUsingReflection(this.advised, method, args); }
Object retVal;
if (this.advised.exposeProxy) { // Make invocation available if necessary. oldProxy = AopContext.setCurrentProxy(proxy); setProxyContext = true; }
// Get as late as possible to minimize the time we "own" the target, // in case it comes from a pool. //目标对象：com.tdl.spring.aop.service.impl.MyServiceImpl target = targetSource.getTarget(); Class<?> targetClass = (target != null ? target.getClass() : null);
// Get the interception chain for this method. //获取方法的拦截器链，我们只配置了一个：myAdvisor List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);
// Check whether we have any advice. If we don't, we can fallback on direct // reflective invocation of the target, and avoid creating a MethodInvocation. if (chain.isEmpty()) { // 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 = AopUtils.invokeJoinpointUsingReflection(target, method, argsToUse); } else { // We need to create a method invocation... 封装一个方法调用 MethodInvocation invocation = new ReflectiveMethodInvocation(proxy, target, method, args, targetClass, chain); // Proceed to the joinpoint through the interceptor chain. //执行方法调用 retVal = invocation.proceed(); }
// Massage return value if necessary. Class<?> returnType = method.getReturnType(); if (retVal != null && retVal == target && returnType != Object.class && returnType.isInstance(proxy) && !RawTargetAccess.class.isAssignableFrom(method.getDeclaringClass())) { // Special case: it returned "this" and the return type of the method // is type-compatible. Note that we can't help if the target sets // a reference to itself in another returned object. retVal = proxy; } else if (retVal == null && returnType != Void.TYPE && returnType.isPrimitive()) { throw new AopInvocationException( "Null return value from advice does not match primitive return type for: " + method); } return retVal; } finally { if (target != null && !targetSource.isStatic()) { // Must have come from TargetSource. targetSource.releaseTarget(target); } if (setProxyContext) { // Restore old proxy. AopContext.setCurrentProxy(oldProxy); } } }
public Object proceed() throws Throwable { // We start with an index of -1 and increment early. if (this.currentInterceptorIndex == this.interceptorsAndDynamicMethodMatchers.size() - 1) { return invokeJoinpoint(); }
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; Class<?> targetClass = (this.targetClass != null ? this.targetClass : this.method.getDeclaringClass()); if (dm.methodMatcher.matches(this.method, targetClass, this.arguments)) { return dm.interceptor.invoke(this); } else { // Dynamic matching failed. // Skip this interceptor and invoke the next in the chain. //可能的递归调用 return proceed(); } } else { // It's an interceptor, so we just invoke it: The pointcut will have // been evaluated statically before this object was constructed. //interceptorOrInterceptionAdvice是MyAdvisor,MyAdvisor实现了MethodInterceptor //这里会进入MyAdvisor的invoke方法。 return ((MethodInterceptor) interceptorOrInterceptionAdvice).invoke(this); } }
MyAdvisor的逻辑：
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public class MyAdvisor implements MethodInterceptor {
