spring源码系列三（spring aop 2）

在springbean生命周期的时候，我们会看到一个这个注册AnnotationAwareAspectJAutoProxyCreator,我们看一下这个的继承关系uml图

看最上面有一个BeanPostProcessor,这里定义bean实例化前后执行的方法,AbstractAutoProxyCreator这个抽象类实现的，看一下逻辑

public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) {
	Object cacheKey = getCacheKey(beanClass, beanName);


	if (!StringUtils.hasLength(beanName) || !this.targetSourcedBeans.contains(beanName)) {
		if (this.advisedBeans.containsKey(cacheKey)) {
			return null;
		}
		//首先方法内部会进行一系列的判断，判断当前bean是否在advisedBeans中（保存了所有需要增强bean）、判断当前bean是否是基础类型的Advice、Pointcut、Advisor、AopInfrastructureBean、判断是否是切面（是否实现了注解@Aspect）、判断是否需要跳过等。就是就是判断是否需要代理
		if (isInfrastructureClass(beanClass) || shouldSkip(beanClass, beanName)) {
			this.advisedBeans.put(cacheKey, Boolean.FALSE);
			return null;
		}
	}

	// Create proxy here if we have a custom TargetSource.
	// Suppresses unnecessary default instantiation of the target bean:
	// The TargetSource will handle target instances in a custom fashion.
	TargetSource targetSource = getCustomTargetSource(beanClass, beanName);
	if (targetSource != null) {
		if (StringUtils.hasLength(beanName)) {
			this.targetSourcedBeans.add(beanName);
		}
		Object[] specificInterceptors = getAdvicesAndAdvisorsForBean(beanClass, beanName, targetSource);
		//这里就是创建一个代理
		Object proxy = createProxy(beanClass, beanName, specificInterceptors, targetSource);
		this.proxyTypes.put(cacheKey, proxy.getClass());
		return proxy;
	}

	return null;
}

protected Object createProxy(Class<?> beanClass, @Nullable String beanName,
			@Nullable Object[] specificInterceptors, TargetSource targetSource) {

		if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
			AutoProxyUtils.exposeTargetClass((ConfigurableListableBeanFactory) this.beanFactory, beanName, beanClass);
		}

		ProxyFactory proxyFactory = new ProxyFactory();
		proxyFactory.copyFrom(this);

		if (!proxyFactory.isProxyTargetClass()) {
			if (shouldProxyTargetClass(beanClass, beanName)) {
				proxyFactory.setProxyTargetClass(true);
			}
			else {
				evaluateProxyInterfaces(beanClass, proxyFactory);
			}
		}

		Advisor[] advisors = buildAdvisors(beanName, specificInterceptors);
		proxyFactory.addAdvisors(advisors);
		proxyFactory.setTargetSource(targetSource);
		customizeProxyFactory(proxyFactory);

		proxyFactory.setFrozen(this.freezeProxy);
		if (advisorsPreFiltered()) {
			proxyFactory.setPreFiltered(true);
		}

		return proxyFactory.getProxy(getProxyClassLoader());
	}

通过ProxyFactory 这个创建的代理类，ProxyFactory 这个是继承ProxyCreatorSupport这个的

public AopProxy createAopProxy(AdvisedSupport config) throws AopConfigException {
		if (config.isOptimize() || config.isProxyTargetClass() || hasNoUserSuppliedProxyInterfaces(config)) {
			Class<?> targetClass = config.getTargetClass();
			if (targetClass == null) {
				throw new AopConfigException("TargetSource cannot determine target class: " +
						"Either an interface or a target is required for proxy creation.");
			}
			//jdk代理 接口
			if (targetClass.isInterface() || Proxy.isProxyClass(targetClass)) {
				return new JdkDynamicAopProxy(config);
			}
			//还是 cglib
			return new ObjenesisCglibAopProxy(config);
		}
		else {
			return new JdkDynamicAopProxy(config);
		}
	}

这个就是代理创建的过程。下次说什么时候执行