为什么SpringAOP使用JDK动态代理时好像没有代理Object.[equals()、hashCode()、toString()]这三个方法

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Spring的AOP是通过JDK动态代理或者CGLib来生成目标对象的代理对象,然后将增强功能(Aspect【包括了Advice和Pointcut】)织入到符合条件(Pointcut)的类的方法(JoinPoint)上。

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JDK动态代理实现原理 http://rejoy.iteye.com/blog/1627405


//这是JDK动态代理过程中要代理的4个方法
 private static Method m1;
 private static Method m3;
 private static Method m0;
 private static Method m2;

 m1 = Class.forName("java.lang.Object").getMethod("equals", new Class[] { Class.forName("java.lang.Object") });
 m3 = Class.forName("pers.mine.SpringAOP.vo.KongFuInterface").getMethod("random", new Class[0]);
 m0 = Class.forName("java.lang.Object").getMethod("hashCode", new Class[0]);
 m2 = Class.forName("java.lang.Object").getMethod("toString", new Class[0]);

但是spring代理过程中并没有将相应代码插入[equals()、hashCode()、toString()]三个方法中,为什么呢?
答案在org.springframework.aop.framework.JdkDynamicAopProxy类中
这个类实现了InvocationHandler接口,说明SpringAOP是通过这个类实现动态代理的
在这个类的invoke方法中有

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.
            target = targetSource.getTarget();
            if (target != null) {
                targetClass = target.getClass();
            }

            // Get the interception chain for this method.
            List chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);

            // Check whether we have any advice. If we don't, we can fallback on direct
            // reflective invocation of the target, and avoid creating a MethodInvocation.
            if (chain.isEmpty()) {
                // We can skip creating a MethodInvocation: just invoke the target directly
                // Note that the final invoker must be an InvokerInterceptor so we know it does
                // nothing but a reflective operation on the target, and no hot swapping or fancy proxying.
                Object[] argsToUse = AopProxyUtils.adaptArgumentsIfNecessary(method, args);
                retVal = AopUtils.invokeJoinpointUsingReflection(target, method, argsToUse);
            }
            else {
                // We need to create a method invocation...
                invocation = new ReflectiveMethodInvocation(proxy, target, method, args, targetClass, chain);
                // Proceed to the joinpoint through the interceptor chain.
                retVal = invocation.proceed();
            }

            // Massage return value if necessary.
            Class returnType = method.getReturnType();
            if (retVal != null && retVal == target && returnType.isInstance(proxy) &&
                    !RawTargetAccess.class.isAssignableFrom(method.getDeclaringClass())) {
                // Special case: it returned "this" and the return type of the method
                // is type-compatible. Note that we can't help if the target sets
                // a reference to itself in another returned object.
                retVal = proxy;
            }
            else if (retVal == null && returnType != Void.TYPE && returnType.isPrimitive()) {
                throw new AopInvocationException(
                        "Null return value from advice does not match primitive return type for: " + method);
            }
            return retVal;
        }
        finally {
            if (target != null && !targetSource.isStatic()) {
                // Must have come from TargetSource.
                targetSource.releaseTarget(target);
            }
            if (setProxyContext) {
                // Restore old proxy.
                AopContext.setCurrentProxy(oldProxy);
            }
        } 
  

可以看到一开始开始使用if语句过滤了equals()、hashCode()两个方法
toString()有点特殊[先写到这,后续细究吧]。。。

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