JDK动态代理与CGLIB代理

JDK动态代理只能用于有接口的类的代理, 主要用到java.lang.reflect.Proxy类与java.lang.reflect.InvocationHandler接口.

InvocationHandler 用于增强目标类.

Interface object = (Interface) Proxy.newProxyInstance(loader, interfaces, InvocationHandler);

Parameters:

loader the class loader to define the proxy class

interfaces the list of interfaces for the proxy class to implement

InvocationHandler the invocation handler to dispatch method invocations to

 

        /*
         JDK dynamic Proxy
         */
        final Target proxyTarget = new Target();
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        try {
            Class[] clas = {TargetInterface.class};
            TargetInterface instance = (TargetInterface)Proxy.newProxyInstance(loader, clas, new InvocationHandler() {
                @Override
                public Object invoke(Object proxy, Method method, Object[] args)
                        throws Throwable {
                    System.out.println("Before proxy.");
                    Object ret = method.invoke(proxyTarget, args);
                    System.out.println("After proxy.");
                    return ret;
                }
            });

 

 

CGLIB弥补了JDK动态代理只能用于有接口类的代理的缺陷, 可以为任何类代理, 主要用到net.sf.cglib.proxy.Enhancer和net.sf.cglib.proxy.MethodInterceptor接口

MethodInterceptor用于增强目标类.

/*
		 CGLIB Proxy
		 */
		final Target proxyTarget = new Target();
		Enhancer enhancer = new Enhancer();
//		enhancer.setSuperclass(proxyTarget.getClass());
//		enhancer.setCallback(new CGlibProxy(proxyTarget));
//		Target target = (Target)enhancer.create();
		
		Target target = (Target)enhancer.create(Target.class, new MethodInterceptor(){
			@Override
			public Object intercept(Object arg0, Method arg1, Object[] arg2,
					MethodProxy arg3) throws Throwable {
				System.out.println("Before proxy.");
				Object ret = arg1.invoke(proxyTarget, arg2);
				System.out.println("After proxy.");
				return ret;
			}
		});