接口的应用代理设计模式（Proxy）

interface Network {
	public abstract void brower();
}
class Real implements Network {
	public void brower() {
		System.out.println("真实上网");
	}
}
class Proxy implements Network {
	private Network net;
	public Proxy(Network net) {
		this.net = net;//代理主题接受真实主题
	}
	public void check() {
		System.out.println("检查用户是否合法");
	}
	public void brower() {
		this.check();
		this.net.brower();//调用真实的上网操作
	}
}

public class TestDemo {
	public static void main(String[] args) {
		Network net = new Proxy(new Real());
		net.brower();
	}
}