多态

1.

abstract class Car{String name;String color;public Car(){}public Car(String name, String color){this.name = name;this.color = color;}public abstract void run();}class Bmw extends Car{public Bmw(){super();}public Bmw(String name, String color){super(name,color);}public void run(){System.out.println(this.name+"快速地跑了起来..."+this.color );}}class Bsj extends Car{public Bsj(){super();}public Bsj(String name, String color){super(name,color);}public void run(){System.out.println(this.name+"慢慢地跑了起来..."+this.color );}}class CarFactory{String name;//Car bmw = new Bmw();//Car bsj = new Bsj();public CarFactory(String name){this.name = name;}//public Car produce()//{//int a = (int)Math.round(Math.random()*1);//if(a == 0)//return bmw;//else //return bsj;//}public Car produce(){int a = (int)Math.round(Math.random()*1);if(a == 0)return new Bmw("宝马","黑色");elsereturn new Bsj("保时捷","白色");}}public class duotaiPractice{public static void main(String[] args){int x = 0;CarFactory cf = new CarFactory("红太阳制造车厂");while(x<5){Car c = cf.produce();c.run();x++;}}}

宝马快速地跑了起来...黑色
保时捷慢慢地跑了起来...白色
宝马快速地跑了起来...黑色
保时捷慢慢地跑了起来...白色
保时捷慢慢地跑了起来...白色
 


 


 


2. 接口关系下的多态

interface Dao{public abstract void add();public abstract void delete();}class UserDao implements Dao{public  void add(){System.out.println("增");}public  void delete(){System.out.println("删");}}public class InterfaceDuotai {public static void main(String[] args) {Dao d = new UserDao();d.add();d.delete();}}

运行结果：


增
删