Java 零钱通小项目练习，感谢韩老师

感谢韩顺平大神！！！请大家多多关注转发！！！

package com.joshua317;

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

public class Main {

    public static void main(String[] args) {
        ChangeSystem changeSystem = new ChangeSystem();
        Scanner scanner = new Scanner(System.in);
        String number;
        do {
            System.out.println("1.零钱明细");
            System.out.println("2.收入");
            System.out.println("3.消费");
            System.out.println("4.退出");
            System.out.println("请输入要处理的选项：");
            try {
                number = scanner.next();
                switch (number) {
                    case "1":
                        changeSystem.detail();
                        break;
                    case "2":
                        changeSystem.increment();
                        break;
                    case "3":
                        changeSystem.expend();
                        break;
                    case "4":
                        changeSystem.exit();
                        break;
                    default:
                        System.out.println("===============重新输入==============\n");
                }
            }catch (Exception exception) {
                System.out.println("警告：请输入正确的内容\n");
            }

        }while (changeSystem.flag);

    }

    /**
     * 面向过程
     */
    public static void procedureOriented()
    {
        System.out.println("===============零钱包管理小demo===============");
        String number;
        boolean flag = true;
        Scanner scanner = new Scanner(System.in);
        String change = "";
        double totalMoney = 0.0;
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        do {
            System.out.println("1.零钱明细");
            System.out.println("2.收入");
            System.out.println("3.消费");
            System.out.println("4.退出");
            System.out.println("请输入要处理的选项：");

            try {
                number = scanner.next();
                switch (number) {
                    case "1":
                        System.out.println("===============1.零钱明细===============\n");
                        System.out.println("收入\t\t金额\t\t\t余额\t\t\t日期\n");
                        System.out.println(change);
                        break;
                    case "2":
                        System.out.println("===============2.收入===============");
                        System.out.println("请输入收入的金额：");
                        double increment = scanner.nextDouble();
                        if (0 >= increment) {
                            System.out.println("输入金额不能小于0，请重新输入");
                            continue;
                        }
                        totalMoney += increment;
                        Date date = new Date();
                        change += "收入\t\t" + "+" + increment +"\t\t"+ totalMoney + "\t\t" + simpleDateFormat.format(date) +"\n";
                        break;
                    case "3":
                        System.out.println("===============3.消费===============\n");
                        System.out.println("请输入消费的金额：");
                        double increment2 = scanner.nextDouble();
                        if (0 >= increment2) {
                            System.out.println("输入消费金额不能小于0，请重新输入");
                            continue;
                        }
                        if (increment2 > totalMoney) {
                            System.out.println("余额不足，请及时挣钱补充收入");
                            continue;
                        }
                        System.out.println("请输入消费事项:");
                        String consume = scanner.next();
                        totalMoney -= increment2;
                        Date date2 = new Date();
                        change += consume+"\t\t" + "-" + increment2 +"\t\t"+ totalMoney + "\t\t" + simpleDateFormat.format(date2) +"\n";
                        break;
                    case "4":
                        System.out.println("===============4.退出===============\n");
                        flag = false;
                        break;
                    default:
                        System.out.println("===============重新输入==============\n");
                }
            }catch (Exception exception) {
                System.out.println("警告：请输入正确的内容\n");
            }

        }while (flag);
    }
}

/**
 * 面向对象
 */
class ChangeSystem {
    boolean flag = true;
    Scanner scanner = new Scanner(System.in);
    String change = "";
    double totalMoney = 0.0;
    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    //收入
    public void increment()
    {
        System.out.println("===============2.收入===============");
        System.out.println("请输入收入的金额：");
        double increment = scanner.nextDouble();
        if (0 >= increment) {
            System.out.println("输入金额不能小于0，请重新输入");
            return;
        }
        totalMoney += increment;
        Date date = new Date();
        change += "收入\t\t" + "+" + increment +"\t\t"+ totalMoney + "\t\t" + simpleDateFormat.format(date) +"\n";
    }
    //支出
    public void expend()
    {
        System.out.println("===============3.消费===============\n");
        System.out.println("请输入消费的金额：");
        double increment2 = scanner.nextDouble();
        if (0 >= increment2) {
            System.out.println("输入消费金额不能小于0，请重新输入");
            return;
        }
        if (increment2 > totalMoney) {
            System.out.println("余额不足，请及时挣钱补充收入");
            return;
        }
        System.out.println("请输入消费事项:");
        String consume = scanner.next();
        totalMoney -= increment2;
        Date date2 = new Date();
        change += consume+"\t\t" + "-" + increment2 +"\t\t"+ totalMoney + "\t\t" + simpleDateFormat.format(date2) +"\n";
    }
    //明细
    public void detail()
    {
        System.out.println("===============1.零钱明细===============\n");
        System.out.println("收入\t\t金额\t\t\t余额\t\t\t日期\n");
        System.out.println(change);
    }
    //退出
    public void exit()
    {
        System.out.println("===============4.退出===============\n");
        flag = false;
    }
}