Java 动态代理

Java 动态代理远近闻名，写一个简单示例，以便日后扩展学习

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;
import java.lang.reflect.Method;
import java.util.Vector;
import java.util.List;

public class VectorProxy implements InvocationHandler
{
    private Object proxyobj;


    public VectorProxy(Object obj)
    {
        proxyobj = obj;
    }

public static Object factory(Object obj)
    {
Class cls = obj.getClass();

        return Proxy.newProxyInstance( cls.getClassLoader(),
            cls.getInterfaces(),
            new VectorProxy(obj) );
    }

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
    {
System.out.println("before calling " + method);

        if (args != null)
        {
for (int i=0; i<args.length; i++)
            {
                System.out.println(args[i] + "");
            }
}

        Object o = method.invoke(proxyobj, args);

System.out.println("after calling " + method);

        return o;
    }

    public static void main(String[] args)
    {
List v = null;

        v = (List) factory(new Vector(10));

        v.add("New");
        v.add("York");
    }
}

输出结果:
before calling public abstract boolean java.util.List.add(java.lang.Object)
New
after calling public abstract boolean java.util.List.add(java.lang.Object)
before calling public abstract boolean java.util.List.add(java.lang.Object)
York
after calling public abstract boolean java.util.List.add(java.lang.Object)