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

public class ListProxy {
    public static void main(String[] args) throws Exception {
        List<String> list = newList(String.class);
        list.add("abc");
        System.out.println(list);
    }
    
    
    @SuppressWarnings("unchecked")
    public static <T> List<T> newList(Class<T> elementType) {
        return (List<T>)Proxy.newProxyInstance(List.class.getClassLoader(), new Class[]{List.class}, new InvocationHandler() {
            private List<T> realList = new ArrayList<T>();
            public Object invoke(Object proxy, Method method, Object[] args)
                    throws Throwable {
                long start = System.nanoTime();
                Object ret = method.invoke(realList, args);
                long end = System.nanoTime();
                System.out.println("调用" + method.getName() + "耗时:" + (end - start) + "纳秒");
                return ret;
            }
        });
    }
}