public class Proxy {

//通过组合的方式 开闭原则        public static void main(String agrs[]) {                    Greeting greeting = new GreetProxy(new GreetingImpl());                    greeting.sayHello("king");        }

}

interface Greeting {

void sayHello(String name);

}

class GreetingImpl implements Greeting {

public void sayHello(String name) {                    System.out.println("hello  " + name);        }

}

class GreetProxy implements Greeting {

GreetingImpl gi;        public GreetProxy(GreetingImpl impl) {                    gi = impl;        }        public void sayHello(String name) {                    before();    //相当于AOP中的前置增强                    gi.sayHello(name);        }        private void before() {                    System.out.println("before ...");        }

}