接口的上溯造型——《Thinking in Java》随笔015

 1 //: Adventure.java
 2 package cn.skyfffire;
 3 
 4 /**
 5  * 
 6  * @author skyfffire
 7  *
 8  * 此类用于研究接口的上溯造型
 9  */
10 interface CanFight {
11     void fight();
12 }
13 
14 interface CanSwim {
15     void swim();
16 }
17 
18 interface CanFly {
19     void fly();
20 }
21 
22 class ActionCharacter {
23     public void fight() {}
24 }
25 
26 class Hero extends ActionCharacter 
27     implements CanFight, CanSwim, CanFly {
28     
29     @Override
30     public void fight() {
31         System.out.println("fight function run.");
32     }
33     
34     @Override
35     public void swim() {
36         System.out.println("swim function run.");
37     }
38     
39     @Override
40     public void fly() {
41         System.out.println("fly function run.");
42     }
43 }
44 
45 public class Adventure {
46     static void t(CanFight x) {
47         x.fight();
48     }
49     
50     static void u(CanSwim x) {
51         x.swim();
52     }
53     
54     static void v(CanFly x) {
55         x.fly();
56     }
57     
58     static void w(ActionCharacter x) {
59         x.fight();
60     }
61     
62     public static void main(String[] args) {
63         Hero i = new Hero();
64         
65         t(i);
66         u(i);
67         v(i);
68         w(i);
69     }
70 }
71 
72 ///:~

可以发现，类/抽象类/接口都可以进行上溯造型，而且实现多个接口的类可以对任意一个接口进行上溯造型