【OOP】零钱通项目

public class SmallChangeSysApp {
    public static void main(String[] args) {
        new SmallChangeSysOOP().Menu();
    }
}

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;


public class SmallChangeSysOOP {
//    SmallChangeSys smallChangeSys = new SmallChangeSys();
    Scanner scanner = new Scanner(System.in);
    boolean flag = true;
    String key = "";
    String details = "---------------零钱通明细---------------";
    double money = 0;
    double balance = 0;//余额
    Date date = new Date();//日期
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
    String storeName = "";//消费说明
    char answer;
    //完成显示菜单
    public void Menu() {
        do {
            //菜单
            System.out.println("n-------------零钱通菜单(OOP)---------------");
            System.out.println("             1 零钱通明细               ");
            System.out.println("             2 收益入账                 ");
            System.out.println("             3 消费                    ");
            System.out.println("             4 退出                    ");
            System.out.print("请选择(1-4):");
            key = scanner.next();
            switch (key) {
                case "1":
                    this.details();
                    break;
                case "2":
                 this.income();
                    break;
                case "3":
                    this.consumption();
                    break;
                case "4":
                    this.exit();
                    break;
                default:
                    System.out.println("输入有误，重新输入。");
            }
        } while (flag);
    }
    //完成零钱通明细
    public void details() {
        System.out.println(details);
    }
    //完成收益入账
    public void income() {
        System.out.print("收益入账金额：");
        money = scanner.nextDouble();
        
        if (money <= 0) { //入账金额不能为负数
            System.out.println("入账金额不能为负数...");
            return;//退出方法，不再执行后面的代码。
        }
        balance += money;//入账后的余额
        date = new Date();//获取当前日期
        //拼接信息到details
        details += "n收益入账t" + "+" + money + "t" +
                sdf.format(date) + "t" + "余额：" + balance;

    }
    //完成消费
    public void consumption() {
        System.out.print("消费说明：");
        storeName = scanner.next();
        System.out.print("消费金额：");
        money = scanner.nextDouble();
        
        if (money > balance || money <= 0) {//消费金额不能大于余额
            System.out.println("您的消费金额应该在0-" + balance);
            return;
        }
        balance -= money;//消费后的余额
        date = new Date();//获取当前日期
        //拼接信息到details
        details += "n" + storeName + "t" + "-" + money +
                "t" + sdf.format(date) + "t" + "余额：" + balance;
    }
    //完成退出功能
    public void exit() {
        while (true) {
            System.out.println("你确定要退出吗？y/n");
            answer = scanner.next().charAt(0);
            if (answer == 'y' || answer == 'n') {
                break;
            }
        }
        if (answer == 'y') {
            flag = false;
        }
    }
}