java 类的继承与多态性 /接口多态

 

1:class

class Animal {
    private String name;
    Animal(String name) {this.name = name;}
    
    public void enjoy() {
        System.out.println("叫声");
    }
}
class Cat extends Animal{
    private String eyesColor ;
    Cat(String name,String eyesColor){super(name);this.eyesColor = eyesColor;}
    
    public void enjoy() {
        System.out.println("mimi");
    }
}

class Dog extends Animal{
    private String furColor;
    Dog(String name,String furColor){
        super(name);
        this.furColor = furColor;
    }
    
    public void enjoy(){
        System.out.println("汪汪");    
    }
}

class Lady {
    private String name;
    private Animal pet;
    Lady(String name,Animal pet) {
        this.name = name;
        this.pet  = pet;
    }
    public void petEnjoy(){
        pet.enjoy();
    }
}
public class TestAn {
    public static void main(String[] args) {
        Cat c = new Cat("猫","蓝色");
        Lady l1 = new Lady("小丽",c);
        l1.petEnjoy();
        
        Dog d = new Dog("狗","黄色");
        Lady l2 = new Lady("小丹",d);
        l2.petEnjoy();
        
        Animal a = new Animal("老鼠");
        Lady l3 = new Lady("小红",a);
        l3.petEnjoy();
    }
}

 

 

2:interface 

interface Singer {
    public void sing();
    public void sleep();
}
interface Painter {
    public void paint();
    public void eat();
}
class Student implements Singer {
    private String name;
    Student(String name){this.name = name;}
    public void study() {
        System.out.println("Studying");
    }
    public String  getName() {
        return name;
    }
    public void sing() {
        System.out.println("this is student sing");
    }
    public void sleep() {
        System.out.println("this is student sleep");
    }
}

class Teacher implements Singer,Painter {
    private String name;
    Teacher(String name){this.name = name;}
    
    public String getName(){
        return name;
    }
    public void sing() {
        System.out.println("this is teacher singing");
    }
    public void sleep() {
        System.out.println("this is teacher Sleeping");    
    }
    public void paint() {
        System.out.println("this is teacher painting");
    }
    public void eat() {
        System.out.println("this is teacher eating");
    }
    //必须实现所有的接口方法，抽象类不必。
}
public class TestImp {
    public static void main(String[] args) {
        Singer s1 = new Student("xiaodan");
        s1.sing();s1.sleep();
        Singer s2 = new Teacher("me");
        s2.sing();s2.sleep();
      Painter p1 = (Painter)s2;
      p1.paint();p1.eat();
    }    
    
}