代理模式

public class NetWorkTest {
    public static void main(String[] args) {
         Server server = new Server();
         ProxyServer proxyServer = new ProxyServer(server);
         //虽然调用的是 proxyServer.browse() , 但是Server.browse()也执行了
         proxyServer.browse();
    }
}

//定义接口
interface NetWork {
    public void browse();
}

//被代理类
class Server implements NetWork {

    @Override
    public void browse() {
        System.out.println("服务器访问网络");
    }
}

//代理类
class ProxyServer implements NetWork {

    private NetWork work;

    public ProxyServer(NetWork work) {
        this.work = work;
    }

    public void check() {
        System.out.println("联网之前的检查工作");
    }

    @Override
    public void browse() {
        check();
        work.browse();
    }

}