自己写的第一个java项目！

项目名为“零钱通”

细节参考

【零基础 快速学Java】韩顺平 零基础30天学会Java

基本版：

  1 package project;
  2
  3 import java.text.SimpleDateFormat;
  4 import java.util.Date;
  5 import java.util.Scanner;
  6
  7 public class SmallChangeSys {
  8     public static void main(String[] args) {
  9         //1.零钱通菜单
 10         boolean loop = true;
 11         Scanner scanner = new Scanner(System.in);
 12         String key = "";
 13         //2.零钱通明细
 14         String details = "==============零钱通明细==============";
 15         //3.收益入账
 16         double money = 0;
 17         double balance = 0;
 18         Date date = null;
 19         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");//用于日期格式化的
 20         //4.零钱通消费
 21         String note = "";
 22         //5.零钱通退出确认
 23         String choice = "";
 24         //6.判断金额入账和消费时金额是否合理
 25
 26         do {
 27             System.out.println("==============零钱通菜单==============");
 28             System.out.println("\t\t\t1 零钱通明细");
 29             System.out.println("\t\t\t2 收益入账");
 30             System.out.println("\t\t\t3 消费");
 31             System.out.println("\t\t\t4 退    出");
 32
 33             System.out.println("请选择1-4");
 34             key = scanner.next();
 35
 36             //switch 控制
 37             switch (key) {
 38                 case "1":
 39                     System.out.println(details);
 40                     break;
 41                 case "2":
 42                     System.out.println("收益入账金额");
 43                     money = scanner.nextDouble();
 44                     //money范围校验
 45                     if (money <= 0) {
 46                         System.out.println("收益入账金额范围 需要 大于 0");
 47                         break;
 48                     }
 49                     balance += money;
 50                     //拼接信息到收益入账
 51                     date = new Date();//获取当前日期
 52                     details += "\n收益入账\t+" + money + "\t" + sdf.format(date) + "\t" + balance;
 53                     break;
 54                 case "3":
 55                     System.out.println("3 消费");
 56                     money = scanner.nextDouble();
 57                     //money范围校验
 58                     if (money <= 0 || money > balance) {
 59                         if (money <= 0){
 60                             System.out.println("您的消费金额应该 大于 0");
 61                             break;
 62                         }else{
 63                             System.out.println("消费不能透支余额!");
 64                             break;
 65                         }
 66                     }
 67
 68                     System.out.println("消费说明");
 69                     note = scanner.next();
 70                     balance -= money;
 71                     date = new Date();//获取当前日期
 72                     details += "\n" + note + "\t-" + money + "\t" + sdf.format(date) + "\t" + balance;
 73                     break;
 74                 case "4":
 75                     System.out.println("4 退     出");
 76
 77                     while (true) {
 78                         System.out.println("你确定要退出吗?y/n");
 79                         choice = scanner.next();
 80                         if ("y".equals(choice) || "n".equals(choice)) {
 81                             break;
 82                         }
 83
 84                     }
 85                     //当用户退出while后再判断choice是y还是n,就可以决定是否退出
 86                     if ("y".equals(choice)) {
 87                         loop = false;
 88                     }
 89
 90                     break;
 91                 default:
 92                     System.out.println("选择有误，请重新选择");
 93                     break;
 94             }
 95         } while (loop);
 96         System.out.println("==============退出了零钱通项目==============");
 97
 98
 99     }
100 }

OOP版

SmallChangeSysOOP:

  1 package project;
  2
  3 import java.text.SimpleDateFormat;
  4 import java.util.Date;
  5 import java.util.Scanner;
  6
  7 /**
  8  * 该类完成零钱通的各个功能
  9  * 要求使用OOP(面向对象)
 10  */
 11 public class SmallChangeSysOOP {
 12     //属性
 13     //1.零钱通菜单
 14     boolean loop = true;
 15     Scanner scanner = new Scanner(System.in);
 16     String key = "";
 17     //2.零钱通明细
 18     String details = "==============零钱通明细==============";
 19     //3.收益入账
 20     double money = 0;
 21     double balance = 0;
 22     Date date = null;
 23     SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");//用于日期格式化的
 24     //4.零钱通消费
 25     String note = "";
 26     //5.零钱通退出确认
 27     String choice = "";
 28     //6.判断金额入账和消费时金额是否合理
 29
 30     //完成零钱通菜单
 31     public void mainMenu(){
 32         do {
 33             System.out.println("============零钱通菜单(OOP)============");
 34             System.out.println("\t\t\t1 零钱通明细");
 35             System.out.println("\t\t\t2 收益入账");
 36             System.out.println("\t\t\t3 消费");
 37             System.out.println("\t\t\t4 退    出");
 38
 39             System.out.println("请选择1-4");
 40             key = scanner.next();
 41
 42             //switch 控制
 43             switch (key) {
 44                 case "1":
 45                     this.detail();
 46                     break;
 47                 case "2":
 48                     this.income();
 49                     break;
 50                 case "3":
 51                    this.pay();
 52                    break;
 53                 case "4":
 54                    this.exit();
 55                    break;
 56                 default:
 57                     System.out.println("选择有误，请重新选择");
 58                     break;
 59             }
 60         } while (loop);
 61     }
 62     //完成零钱通明细
 63     public void detail(){
 64         System.out.println(details);
 65     }
 66     //完成收益入账
 67     public void income(){
 68         System.out.println("收益入账金额");
 69         money = scanner.nextDouble();
 70         //money范围校验
 71         if (money <= 0) {
 72             System.out.println("收益入账金额范围 需要 大于 0");
 73             return;//退出方法，不再执行后面的代码
 74         }
 75         balance += money;
 76         //拼接信息到收益入账
 77         date = new Date();//获取当前日期
 78         details += "\n收益入账\t+" + money + "\t" + sdf.format(date) + "\t" + balance;
 79     }
 80     //完成消费
 81     public void pay(){
 82         System.out.println("3 消费");
 83         money = scanner.nextDouble();
 84         //money范围校验
 85         if (money <= 0 || money > balance) {
 86             if (money <= 0){
 87                 System.out.println("您的消费金额应该 大于 0");
 88                 return;
 89             }else{
 90                 System.out.println("消费不能透支余额!");
 91                 return;
 92             }
 93         }
 94
 95         System.out.println("消费说明");
 96         note = scanner.next();
 97         balance -= money;
 98         date = new Date();//获取当前日期
 99         details += "\n" + note + "\t-" + money + "\t" + sdf.format(date) + "\t" + balance;
100     }
101     //退出
102     public void exit(){
103         System.out.println("4 退     出");
104
105         while (true) {
106             System.out.println("你确定要退出吗?y/n");
107             choice = scanner.next();
108             if ("y".equals(choice) || "n".equals(choice)) {
109                 break;
110             }
111
112         }
113         //当用户退出while后再判断choice是y还是n,就可以决定是否退出
114         if ("y".equals(choice)) {
115             loop = false;
116         }
117     }
118
119 }

SmallChangeSysApp:

 1 package project;
 2
 3
 4 /**
 5  * 直接调用SmallChangeSysOOP对象，显示主菜单
 6  */
 7 public class SmallChangeSysApp {
 8     public static void main(String[] args) {
 9         new SmallChangeSysOOP().mainMenu();
10     }
11 }

感谢韩老师精细的视频讲解，推荐新入行的小伙伴学习

链接：【零基础 快速学Java】韩顺平 零基础30天学会Java_哔哩哔哩_bilibili