Java-加油站支付小案例

需求：

这个小案例可以复习和理解多态的知识。 

实现： 

1.创建Card类（父类）

package com.itheima.demo2;

public class Card {
    private String carId;
    private String name;
    private double money;
    private String phone;
    public Card() {
    }
    public Card(String carId, String name, double money, String phone) {
        this.carId = carId;
        this.name = name;
        this.money = money;
        this.phone = phone;
    }
    public String getCarId() {
        return carId;
    }
    public void setCarId(String carId) {
        this.carId = carId;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public double getMoney() {
        return money;
    }
    public void setMoney(double money) {
        this.money = money;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    //预存金额
    public void deposit(double money) {
        this.money += money;
    }
    //消费金额
    public void consume(double money) {
        this.money -= money;
    }
}

2.创建金卡和银卡类 

金卡和银卡需要继承至Card类，并且重写comsume方法，并且提供有参构造器 

金：

package com.itheima.demo2;

public class GoldCard extends Card{
    public GoldCard(String carId, String name, double money, String phone) {
        super(carId, name, money, phone);
    }

    @Override
    public void consume(double money){
        System.out.println("您当前消费"+money);
        System.out.println("尊贵的金卡用户打折后消费"+money*0.8);
        if(money*0.8>getMoney()) {
            System.out.println("余额不足，请充值");
            return;
        }
        setMoney(getMoney()-money*0.8);
        if(money*0.8>=200) {
            System.out.println("请打印洗车票");
        }
    }

}

银：

package com.itheima.demo2;

public class YingCard extends Card{
    public YingCard(String carId, String name, double money, String phone) {
        super(carId, name, money, phone);
    }

    @Override
    public void consume(double money){
        System.out.println("您当前消费"+money);
        System.out.println("尊贵的银卡用户打折后消费"+money*0.9);
        if(money*0.9>getMoney()) {
            System.out.println("余额不足，请充值");
            return;
        }
        setMoney(getMoney()-money*0.9);

    }
}

3.创建对象，实现方法

package com.itheima.demo2;
import java.util.Scanner;
public class Test {
    public static void main(String[] args) {
        GoldCard gold = new GoldCard("渝A9999", "张三", 5000, "12345678901");
        YingCard ying = new YingCard("渝A0000", "李四", 2000, "12347852901");

        pay(gold);
        pay(ying);
    }

    public static void pay(Card c){
        System.out.println("当前消费:");
        Scanner sc=new Scanner(System.in);
        double money=sc.nextDouble();
        c.consume(money);
    }
}

这里pay方法直接传入Card类，利用多态的特点，不用多加金银卡的判断。 

运行结果：

当前消费:
600
您当前消费600.0
尊贵的金卡用户打折后消费480.0
请打印洗车票
当前消费:
2230
您当前消费2230.0
尊贵的银卡用户打折后消费2007.0
余额不足，请充值

好了，就这样了，写的不详细，在图书馆，电脑没电马上关机了┭┮﹏┭┮。 理解一下。