springAOP——代理对象的产生及方法调用

代理对象的创建
getObject--》
void org.springframework.aop.framework.ProxyFactoryBean.initializeAdvisorChain() throws AopConfigException, BeansException
初始化拦截器链路--》
addAdvisorOnChainCreation(advice, name);找到advisor并添加--》
this.advisors.add(pos, advisor);设置advisors集合。--》
然后创建代理对象，可以用JDK动态代理或者CGLIB字节码加强。
ProxyFactoryBean继承了AdvisedSupport，在创建AopProxy（例如org.springframework.aop.framework.JdkDynamicAopProxy）实例的时候会把自己传递过去，也就是AopProxy持有一个AdvisedSupport，也就只有了advisors——》简单来说，aop代理对象知道自己上有哪些拦截器（通知器），在invoke的时候来解析。--》

invoke 以JDK动态代理为例
 Object org.springframework.aop.framework.JdkDynamicAopProxy.invoke(Object proxy, Method method, Object[] args)
//目标对象
target = targetSource.getTarget();
// Get the interception chain for this method.
List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);
获取拦截器链路
然后构造一个MethodInvocation——invocation = new ReflectiveMethodInvocation(proxy, target, method, args, targetClass, chain);递归调用

拦截器链路的获取：List<Object> org.springframework.aop.framework.AdvisedSupport.getInterceptorsAndDynamicInterceptionAdvice(Method method, Class targetClass)回归到了AdvisedSupport
cached = this.advisorChainFactory.getInterceptorsAndDynamicInterceptionAdvice(
     this, method, targetClass);--》
List<Object> org.springframework.aop.framework.DefaultAdvisorChainFactory.getInterceptorsAndDynamicInterceptionAdvice(Advised config, Method method, Class targetClass)
 boolean hasIntroductions = hasMatchingIntroductions(config, targetClass);//检查是否有IntroductionAdvisor配置
 for (Advisor advisor : config.getAdvisors()) {开始处理config其实就是我们前面提到的那个AdvisedSupport，它代表了配置，持有所有通知器
 。。。
 MethodInterceptor[] interceptors = registry.getInterceptors(advisor);//Advisor中提取MethodInterceptor，这个很重要，不管是通知还是拦截器统统转换为MethodInterceptor
 --》
  MethodInterceptor[] org.springframework.aop.framework.adapter.DefaultAdvisorAdapterRegistry.getInterceptors(Advisor advisor) throws UnknownAdviceTypeException
 这是一个适配器，可以处理本来就是MethodInterceptor的，也可以处理各种Advice（如MethodBeforeAdvice）：
   //如果是MethodInterceptor
  if (advice instanceof MethodInterceptor) {
   interceptors.add((MethodInterceptor) advice);
  }
  //如果是其他通知器
  for (AdvisorAdapter adapter : this.adapters) {//各种适配器将Advice转换为MethodInterceptor
   if (adapter.supportsAdvice(advice)) {
    interceptors.add(adapter.getInterceptor(advisor));
   }
  }
  adapter有三种：MethodBeforeAdviceAdapter、AfterReturningAdviceAdapter、ThrowsAdviceAdapter他们都实现了这样的接口adapter.getInterceptor(advisor)，如
 class MethodBeforeAdviceAdapter implements AdvisorAdapter, Serializable {

 public boolean supportsAdvice(Advice advice) {
  return (advice instanceof MethodBeforeAdvice);
 }
 //将MethodBeforeAdvice提取出来转换成MethodBeforeAdviceInterceptor（实现了MethodInterceptor接口），那么在构造MethodInvocation一次调用各拦截器invoke方法的时候，就变成了前置、后置、环绕处理。
 public MethodInterceptor getInterceptor(Advisor advisor) {
  MethodBeforeAdvice advice = (MethodBeforeAdvice) advisor.getAdvice();
  return new MethodBeforeAdviceInterceptor(advice);
 }

}