Java 接口和多态练习

我们鼠标和键盘实现USB接口，那么我们鼠标和键盘就变成了USB设备，这时候我们就可以把它放到笔记本电脑里面去用

 1 package com.biggw.day10.demo07;  2   3 /**  4  * @author gw  5  * @date 2019/11/2 0002 下午 16:46  6  */  7 public class Computer {  8     public void open() {  9         System.out.println("打开电脑!"); 10     } 11  12     public void close() { 13         System.out.println("关闭电脑!"); 14     } 15  16     public void useDevice(Usb usb) { 17         if (usb instanceof KeyBorad) { 18             KeyBorad keyBorad = (KeyBorad) usb; 19             keyBorad.open(); 20             keyBorad.type(); 21             keyBorad.close(); 22         } else if (usb instanceof Mouse) { 23             Mouse mouse = (Mouse) usb; 24             mouse.open(); 25             mouse.click(); 26             mouse.close(); 27         } 28     } 29 }

 1 package com.biggw.day10.demo07;  2   3 /**  4  * @author gw  5  * @date 2019/11/2 0002 下午 16:42  6  */  7 public interface Usb {  8     public abstract void open();  9  10     public abstract void close(); 11 }

 1 package com.biggw.day10.demo07;  2   3 /**  4  * @author gw  5  * @date 2019/11/2 0002 下午 16:44  6  */  7 public class Mouse implements Usb {  8     @Override  9     public void open() { 10         System.out.println("打开鼠标！"); 11     } 12  13     @Override 14     public void close() { 15         System.out.println("关闭鼠标!"); 16     } 17  18     public void click() { 19         System.out.println("点击鼠标!"); 20     } 21 }

 1 package com.biggw.day10.demo07;  2   3 /**  4  * @author gw  5  * @date 2019/11/2 0002 下午 16:43  6  */  7 public class KeyBorad implements Usb {  8     @Override  9     public void open() { 10         System.out.println("打开键盘!"); 11     } 12  13     @Override 14     public void close() { 15         System.out.println("关闭键盘!"); 16     } 17  18     public void type() { 19         System.out.println("键盘输入文字!"); 20     } 21 }

 1 package com.biggw.day10.demo07;  2   3 /**  4  * @author gw  5  * @date 2019/11/2 0002 下午 16:52  6  */  7 public class Main {  8     public static void main(String[] args) {  9         Usb usb = new KeyBorad(); 10         Usb usb1 = new Mouse(); 11  12         Computer computer = new Computer(); 13         computer.open(); 14         computer.useDevice(usb); 15         computer.useDevice(usb1); 16         computer.close(); 17  18         /*点击鼠标! 19         打开电脑! 20         打开键盘! 21         键盘输入文字! 22         关闭键盘! 23         打开鼠标！ 24         关闭鼠标! 25         关闭电脑!*/ 26     } 27 }

来源：博客园

作者：何去何从gw

链接：https://www.cnblogs.com/biggw/p/11782843.html