1、用abstract 关键字来修饰一个类时，这个类叫做抽象类：用abstract来修饰一个方法时，该方法叫做抽象方法
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、抽象方法只需被声明，而不需实现
abstract class Aniaml {
public String name;
Animal (String name) {
this.name = name;
public abstract void enjoy();
}
}
class Cat extends Animal {
private String eyeColor;
Cat(String n,String f) {
super(n);
this.eyeColor = eyeColor;
}
public void enjoy() {
System.out.println("猫叫声......");
}
}
class Bird extends Animal {
private String featherColor;
Bird(String n,String f) {
super(n);
featherColor = f;
}
public void enjoy() {
System.out.println("鸟叫声.....");
}
}
class Lady {
private String name;
private Animal pet;
Lady(String name,Animal pet) {
this.name = name;
this.pet = pet;
}
public void myEnjoy(){
pet.enjoy();
}
}
public class Test {
public static void main(String args[]) {
//Lady l3 = new Lady("l3",new Bird("birthname","green"));
Cat c = new Cat("catname","blue");
Bird d = new Bird("dogname","black");
Lady l1 = new Lady("l1",c);
Lady l2 = new Lady("l2",d);
}
}