Core

qiaogege

接口的使用： 1 多态的情况下使用接口：分为编译时和运行时的状态。 2 注意对象的相同性。 3 强制转换的情况。 package com; public interface Animal { } package com; /*** * * 鸟类 * * @author Administrator * */ public class Bird implements Animal { public Bird() { } public String color; private int age; public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getColor() { return color; } public void setColor(String color) { this.color = color; } } package com; public class SamllBird extends Bird { } package com; import java.lang.reflect.InvocationTargetException; public class Test { public static void main(String[] args) throws ClassNotFoundException, SecurityException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException, NoSuchMethodException, InvocationTargetException { Animal b = new Bird(); b.toString(); Bird bird = (Bird)b; bird.setColor("red"); System.out.println(bird.getColor()); System.out.println(b==bird); Animal sb = new SamllBird(); Bird bb = (Bird)sb; System.out.println(sb==bb); System.out.println(b instanceof Animal); System.out.println(bird instanceof Animal); System.out.println(sb instanceof Animal); } } 运行结果： red true true true true true