Spring AOP ProxyFactoryBean源码笔记 二

AopProxy getProxy()方法获取到的代理分为Jdk代理JdkDynamicAopProxy或者Cglib代理ObjenesisCglibAopProxy。代理在生成代理对象时，设置了对应的回调入口。

• Jdk是JdkDynamicAopProxy中用Proxy.newProxyInstance来生成代理对象，对应的回调入口为JdkDynamicAopProxy invoke()方法。
• Cglib是在ObjenesisCglibAopProxy的父类CglibAopProxy中配置了Enhancer来创建代理对象， Enhancer上的回调为 DynamicAdvisedInterceptor， 实际的回调入口为DynamicAdvisedInterceptor intercept()方法

代理类的调用过程：

• Jdk的回调 JdkDynamicAopProxy invoke()

final class JdkDynamicAopProxy implements AopProxy, InvocationHandler, Serializable {
...
    // 顺序1 
    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;
    }
...
@Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        MethodInvocation invocation;
        Object oldProxy = null;
        boolean setProxyContext = false;
        // 顺序1 
        // 在创建Jdk代理的时候，调用了JdkDynamicAopProxy的构造器，new JdkDynamicAopProxy(config)。
        // config即ProxyFactoryBean，保存在JdkDynamicAopProxy的advised属性上。
        // 从ProxyFactoryBean上获取包装后的目标对象
        TargetSource targetSource = this.advised.targetSource;
        Class targetClass = null;
        Object target = null;

        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;
            }

            // May be null. Get as late as possible to minimize the time we "own" the target,
            // in case it comes from a pool.
            // 真正的目标对象
            target = targetSource.getTarget();
            if (target != null) {
                targetClass = target.getClass();
            }

            // Get the interception chain for this method.
            // 顺序2
            // 获取拦截器链
            // 调用的是JdkDynamicAopProxy的基类AdvisedSupport的getInterceptorsAndDynamicInterceptionAdvice()方法
            List