二十三种设计模式全面解析-外观模式（Facade Pattern）详解：简化复杂系统的奇妙之道

// 子系统类：灯光系统
class LightSystem {
    public void turnOn() {
        System.out.println("灯光系统已打开");
    }
    public void turnOff() {
        System.out.println("灯光系统已关闭");
    }
}
// 子系统类：音响系统
class AudioSystem {
    public void play() {
        System.out.println("音响系统正在播放");
    }
    public void stop() {
        System.out.println("音响系统已停止");
    }
}
// 子系统类：投影仪系统
class ProjectorSystem {
    public void start() {
        System.out.println("投影仪系统已启动");
    }
    public void stop() {
        System.out.println("投影仪系统已停止");
    }
}
// 外观类：影院外观
class CinemaFacade {
    private LightSystem lightSystem;
    private AudioSystem audioSystem;
    private ProjectorSystem projectorSystem;
    public CinemaFacade() {
        this.lightSystem = new LightSystem();
        this.audioSystem = new AudioSystem();
        this.projectorSystem = newProjectorSystem();
    }
    public void startMovie() {
        lightSystem.turnOn();
        audioSystem.play();
        projectorSystem.start();
    }
    public void stopMovie() {
        projectorSystem.stop();
        audioSystem.stop();
        lightSystem.turnOff();
    }
}
// 客户端代码
public class Client {
    public static void main(String[] args) {
        CinemaFacade facade = new CinemaFacade();
        facade.startMovie();
        facade.stopMovie();
    }
}
```