AOP原理

• • 1.@EnableAspectJAutoProxy
  • 2.AnnotationAwareAspectJAutoProxyCreator
  • • AbstractAutoProxyCreator

看给容器当中注入了什么组件？这个组件的功能是什么，什么时候开始工作？

1.@EnableAspectJAutoProxy

@EnableAspectJAutoProxy开启基于注解的AOP
  @Import(AspectJAutoProxyRegistrar.class) 为容器中注册bean
    AspectJAutoProxyRegistrar 45
      AopConfigUtils.registerAspectJAnnotationAutoProxyCreatorIfNecessary(registry);
        AopConfigUtils 121 
          注册bean的类型是：AnnotationAwareAspectJAutoProxyCreator.class
          注册bean的id是：internalAutoProxyCreator

2.AnnotationAwareAspectJAutoProxyCreator

继承关系
  AnnotationAwareAspectJAutoProxyCreator
    AspectJAwareAdvisorAutoProxyCreator
      AbstractAdvisorAutoProxyCreator
        AbstractAutoProxyCreator implements SmartInstantiationAwareBeanPostProcessor, BeanFactoryAware 
SmartInstantiationAwareBeanPostProcessor（bean的后置处理器 在bean初始化前后做事）
BeanFactoryAware：自动装配BeanFactory

AbstractAutoProxyCreator

	@Override
	public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
		Object cacheKey = getCacheKey(beanClass, beanName);
		if (beanName == null || !this.targetSourcedBeans.contains(beanName)) {
			if (this.advisedBeans.containsKey(cacheKey)) {
				return null;
			}
			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.
		if (beanName != null) {
			TargetSource targetSource = getCustomTargetSource(beanClass, beanName);
			if (targetSource != null) {
				this.targetSourcedBeans.add(beanName);
				Object[] specificInterceptors = getAdvicesAndAdvisorsForBean(beanClass, beanName, targetSource);
				Object proxy = createProxy(beanClass, beanName, specificInterceptors, targetSource);
				this.proxyTypes.put(cacheKey, proxy.getClass());
				return proxy;
			}
		}
		return null;
	}
	@Override
	public boolean postProcessAfterInstantiation(Object bean, String beanName) {
		return true;
	}	

	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
	}