什么是外观模式? 例如:打开电脑时,在电脑的内部需要执行一下几步，即启动电源、主板、硬盘，最后启动操作系统:关闭电脑时需要执行 的步骤与之正好相反。 关键：1.意图    2.动机     3.适用性   package org.java.test; /** * @author Lee * 功能:定义电源类 Power，并实现启动电源和关闭电源的方法 * @date:2018.11.27 22.23 * * */ public class Power { public void Connect(){ System.out.println("Power Connect"); } public void Disconnect(){ System.out.println("Power Disconnect"); } } package org.java.test; /** * @author Lee * 功能: MainBoard 主板类 ，定义主板开关的方法 * @date:2018.11.27 22.35 * * */ public class MainBoard { public void On(){ System.out.println("MainBoard On"); } public void Off(){ System.out.println("MainBoard Off"); } } package org.java.test; /** * @author Lee * 功能:HardDisk 硬盘 * @date:2018.11.27 22.38 * * */ public class HardDisk { public void Run(){ System.out.println("HardDisk Run"); } public void Stop(){ System.out.println("HardDisk Stop"); } } package org.java.test; /** * @author Lee * 功能: OperateionSystem 操作系统 * @date:2018.11.27 22:47 * * */ public class OperateionSystem { public void Startup(){ System.out.println("OperateionSystem Startup"); } public void Shutdown(){ System.out.println("OperateionSystem Shutdown"); } } package org.java.test; /** * @author Lee * @param:power 电源 * mainBoard 主板 * hardDisk 硬盘 * operateionSystem 操作系统 * @date:2018.11.27 22:51 * * * */ public class Computer { Power power; MainBoard mainBoard; HardDisk hardDisk; OperateionSystem operateionSystem; public Computer(Power power, MainBoard mainBoard, HardDisk hardDisk, OperateionSystem operateionSystem) { super(); this.power = power; this.mainBoard = mainBoard; this.hardDisk = hardDisk; this.operateionSystem = operateionSystem; } //启动计算机 public void StartUp(){ this.power.Connect(); this.hardDisk.Run(); this.operateionSystem.Startup(); } //关闭计算机 public void Shutdown(){ this.hardDisk.Stop(); this.mainBoard.Off(); this.power.Disconnect(); } } package org.java.test; /** * @author Lee * 功能：测试 * @date:2018.11.27 23.08 * * */ public class Program { public static void main(String[] args) { Power power=new Power(); //创建电源对象 MainBoard mainBoard=new MainBoard(); //创建主板对象 HardDisk hardDisk=new HardDisk(); //创建硬盘对象 OperateionSystem operateionSystem=new OperateionSystem(); //创建操作系统对象 Computer computer=new Computer(power, mainBoard, hardDisk, operateionSystem);//创建计算机对象 System.out.println("打开电脑"); computer.StartUp(); System.out.println("关闭电脑"); computer.Shutdown(); } }