抽象类示例

 1 public abstract class Card {
 2     private String name;
 3     private double money;
 4 
 5     public abstract void pay(double money);
 6 
 7     public String getName() {
 8         return name;
 9     }
10 
11     public void setName(String name) {
12         this.name = name;
13     }
14 
15     public double getMoney() {
16         return money;
17     }
18 
19     public void setMoney(double money) {
20         this.money = money;
21     }
22 }

 1 public class GoldCard extends Card{
 2     @Override
 3     public void pay(double money) {
 4         //  优惠后金额
 5         double rs = money * 0.8;
 6         double lastMoney = getMoney() - rs;
 7 
 8         System.out.println(getName() + "当前账户金额：" + getMoney()
 9             + "当前消费：" + rs + "元，当前剩余：" + lastMoney + "元"
10         );
11 
12         setMoney(lastMoney);
13     }
14 }

1 public class Test {
2     public static void main(String[] args) {
3         GoldCard c = new GoldCard();
4         c.setMoney(10000.0);
5         c.setName("张三");
6         c.pay(300);
7     }
8 }