Spring AOP中的责任链设计模式

前言一、示例代码二、DynamicAdvisedInterceptor三、ReflectiveMethodInvocation

前面简单的写了下Spring AOP中是怎么实现动态代理的，简单的来说是通过bean对象的后置管理器对实例化的bean对象做判断后使用不同的动态代理方式，下面来看一下生成的动态代理是怎么执行的。

@Aspect
@Component
public class MyAspect {

	@Pointcut("execution(public void com.jack.service.TestService.doSomething())")
	public void point(){}

	@Before("point()")
	public void beforeMethod(JoinPoint joinPoint) {
		System.out.println("beforeMethod----");
	}

	@After("point()")
	public void afterMethod(JoinPoint joinPoint) {
		System.out.println("afterMethod----");
	}

	@AfterReturning("point()")
	public void AfterReturning() {
		System.out.println("AfterReturning----");
	}

	@AfterThrowing("point()")
	public void AfterThrowing() {
		System.out.println("AfterThrowing----");
	}

	@Around("point()")
	public void around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
		System.out.println("around start---");
		proceedingJoinPoint.proceed();
		System.out.println("around end---");
	}
}

多配置几个通知类型来观察一下这些通知之间是怎么协调调用的。

CGLIB的动态代理主要是依靠MethodInterceptor来实现的，看一下AOP中CglibAopProxy类，在这个类里面有个内部类DynamicAdvisedInterceptor，仔细一看这个类它的父类是MethodInterceptor瞬间就清晰了，这就是最后CGLIB代理的执行类。

private static class DynamicAdvisedInterceptor implements MethodInterceptor, Serializable {

		private final AdvisedSupport advised;

		public DynamicAdvisedInterceptor(AdvisedSupport advised) {
			this.advised = advised;
		}

		@Override
		@Nullable
		public Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
			Object oldProxy = null;
			boolean setProxyContext = false;
			Object target = null;
			//获取代理对象等属性一系列操作
			TargetSource targetSource = this.advised.getTargetSource();
			try {
				if (this.advised.exposeProxy) {
					oldProxy = AopContext.setCurrentProxy(proxy);
					setProxyContext = true;
				}
				target = targetSource.getTarget();
				Class targetClass = (target != null ? target.getClass() : null);
				//获取任务调用链
				List