1、问题描述

小明家的电源总开关控制了家里的三个设备：空调、台灯和电视机。每个设备都有独立的开关密码，分别用数字1、2和3表示。即输入1时，空调关闭，输入2时，台灯关闭，输入3时，电视机关闭，当输入为4时，表示要关闭所有设备。请你使用外观模式编写程序来描述电源总开关的操作。

输入示例
4
1
2
3
4

输出示例
Air Conditioner is turned off.
Desk Lamp is turned off.
Television is turned off.
All devices are off.

2、外观模式

举个例⼦，假设你正在编写的⼀个模块⽤来处理⽂件读取、解析、存储，我们可以将这个过程拆成三部分，然后创建⼀个外观类，将⽂件系统操作、数据解析和存储操作封装在外观类中，为客户端提供⼀个简化的接⼝，如果后续需要修改⽂件处理的流程或替换底层⼦系统，也只需在外观类中进⾏调整

作者认为和代理模式类似，只是目的不一样

3、代码

import java.util.*;public class Main{public static void main(String[] args){Scanner sc=new Scanner(System.in);int number=sc.nextInt();AirConditioner ac=new AirConditioner();TableLamp tl=new TableLamp();TV  tv=new TV();Facade fc=new Facade(ac,tl,tv);for(int i=0;i<number;i++){int n=sc.nextInt();fc.turnOff(n);}}
}
interface Furniture{void turnOff();
}class AirConditioner implements Furniture{@Overridepublic void turnOff() {System.out.println("Air Conditioner is turned off.");}
}class TableLamp implements Furniture{@Overridepublic void turnOff() {System.out.println("Desk Lamp is turned off.");}
}class TV implements Furniture{@Overridepublic void turnOff() {System.out.println("Television is turned off.");}
}class Facade{private AirConditioner ac;private TableLamp tl;private TV tv;public  Facade(AirConditioner a,TableLamp t,TV tv){this.ac=a;this.tl=t;this.tv=tv;}public void turnOff(int tag){if(tag==1){ac.turnOff();}else if(tag==2){tl.turnOff();}else if(tag==3){tv.turnOff();}else {System.out.println("All devices are off.");}}
}