Java之抽象abstract关键字 蔚落 2022-07-14 14:30 131阅读 0赞 1.用abstract关键字修饰一个类时,叫抽象类。用abstract关键字修饰一个方法时,叫抽象方法 2.含有抽象方法的类必须被声明为抽象类,抽象类必须被继承,抽象方法必须被重写 3.抽象类不能被实例化 4.抽象方法只需声明,不需实现 5.继承抽象类的也可以是抽象类,重写的抽象方法还是抽象方法 abstract class Animal { private String name; Animal(String name) { this.name = name; } public abstract void enjoy(); //System.out.println("animalshout..."); } class Cat extends Animal { private String eyesColor; Cat(String n,String c) { super(n); eyesColor = c; } public void enjoy() { System.out.println("catshoult..."); } } class Dog extends Animal { private String furColor; Dog(String n,String c) { super(n); furColor = c; } public void enjoy() { System.out.println("dogshoult..."); } } class Lady { private String name; private Animal pet; Lady(String name, Animal pet) { this.name = name; this.pet = pet; } public void myPetEnjoy() { pet.enjoy(); } } public class TestTai { public static void main(String[] args) { Cat c = new Cat("catname", "blue"); Dog d = new Dog("d ogname", "black"); Lady l1 = new Lady("l1", c); Lady l2 = new Lady("l2", d); l1.myPetEnjoy(); l2.myPetEnjoy(); } }
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