19零钱通项目

## 项目需求

零钱通项目，功能有零钱通明细、收益入账、消费、退出系统

- 用户输入4退出时，给出提示信息为确定要退出吗？ Y/N,必须输入正确的Y/N,，否则循环输入指令，直到输入y或者n；
- 在收益入账和消费时，判断金额是否合理，并给出相应提示

![image-20240301105555032](https://oss.maolin101.com/202501070054997.png-101.webp)

项目先化繁为简

## 面向过程编程

```java
import java.text.SimpleDateFormat;
import java.util.Scanner;
import java.util.Date;
public class SmallChangeSys {
    public static void main(String[] args) {
        boolean loop = true;
        Scanner scanner = new Scanner(System.in);
        String key = "";

// 1.零钱通明细
        String details = "\n----------零钱通明细----------";

//2.收益入账
        double money = 0.0;
        double balance = 0.0; //余额
        Date date = null; //表示当前的日期
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");//可用于日期格式化

//3.消费
        String note = "";

do {
            System.out.println("=========零钱通菜单=========");
            System.out.println("\t1. 零钱通明细");
            System.out.println("\t2. 收益入账");
            System.out.println("\t3. 消费");
            System.out.println("\t4. 退 出");

System.out.println("请选择（1-4）：");
            key = scanner.next();

switch (key){
                case "1":
                    System.out.println(details);
                    break;

case "2":
                    System.out.println("本次收益入账金额：");
                    money = scanner.nextDouble();
                    //money值校验
                    if (money <= 0){
                        System.out.println("收益入账金额需要大于零");
                        break;
                    }

balance += money;
                    date = new Date();//获取到当前的日期
                    details += "\n收益入账\t+" + money + "\t" + sdf.format(date) + "\t" + balance;
                    //System.out.println(details);

break;
                case "3":
                    System.out.println("消费金额：");
                    money = scanner.nextDouble();
                    //消费金额校验
                    if (money > balance  || money <= 0){
                        System.out.println("您的消费金额应该在0-" + balance);
                        break;
                    }

System.out.println("消费说明：");
                    note = scanner.next();
                    balance -= money;
                    date = new Date();//获取到当前的日期
                    details += "\n" + note + "\t-" + money + "\t" + sdf.format(date) + "\t" + balance;

break;
                case "4":
                    String choice = "";
                    //必须输入y或者n
                    while (true){
                        System.out.println("确定要退出吗？y/n");
                        choice = scanner.next();
                        if ("y".equals(choice) || "n".equals(choice)){
                            break;
                        }
                    }

//如果输入y则退出程序
                    if (choice.equals("y")){
                        loop = false;
                    }

break;
                default:
                    System.out.println("输入有误，请重新选择");

}

}while (loop);
        System.out.println("------已退出零钱通项目------");
    }
}

```

![image-20240301133127041](https://oss.maolin101.com/202501070054998.png-101.webp)

## 面向对象编程

SmallChangeSysOOP类 用于完成各个 功能

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

//将每个功能对应一个方法
public class SmallChangeSysOOP {
    boolean loop = true;
    Scanner scanner = new Scanner(System.in);
    String key = "";

// 1.零钱通明细
    String details = "\n----------零钱通明细----------";

//2.收益入账
    double money = 0.0;
    double balance = 0.0; //余额
    Date date = null; //表示当前的日期
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");//可用于日期格式化

//3.消费
    String note = "";

// 主菜单
    public void mainMenu(){
        do {
            System.out.println("=========OOP版本 零钱通菜单=========");
            System.out.println("\t1. 零钱通明细");
            System.out.println("\t2. 收益入账");
            System.out.println("\t3. 消费");
            System.out.println("\t4. 退 出");

System.out.println("请选择（1-4）：");
            key = scanner.next();

switch (key){
                case "1":
                    this.detail();
                    break;

case "2":
                    this.income();
                    break;
                case "3":
                    this.pay();
                    break;
                case "4":
                    this.exit();
                    break;
                default:
                    System.out.println("输入有误，请重新选择");

}

}while (loop);
    }

//零钱通明细
    public void detail(){
        System.out.println(details);
    }

//收益入账
    public void income(){
        System.out.println("本次收益入账金额：");
        money = scanner.nextDouble();
        //money值校验
        if (money <= 0){
            System.out.println("收益入账金额需要大于零");
            return ; //退出方法 不再执行后面的代码
        }

balance += money;
        date = new Date();//获取到当前的日期
        details += "\n收益入账\t+" + money + "\t" + sdf.format(date) + "\t" + balance;
    }

//消费
    public void pay(){
        System.out.println("消费金额：");
        money = scanner.nextDouble();
        //消费金额校验
        if (money > balance  || money <= 0){
            System.out.println("您的消费金额应该在0-" + balance);
            return;
        }

System.out.println("消费说明：");
        note = scanner.next();
        balance -= money;
        date = new Date();//获取到当前的日期
        details += "\n" + note + "\t-" + money + "\t" + sdf.format(date) + "\t" + balance;
    }

//退出功能
    public void exit(){
        String choice = "";
        //必须输入y或者n
        while (true){
            System.out.println("确定要退出吗？y/n");
            choice = scanner.next();
            if ("y".equals(choice) || "n".equals(choice)){
                break;
            }
        }

//如果输入y则退出程序
        if (choice.equals("y")){
            loop = false;
        }
    }

}

```

SmallChangeSysApp类 用于完成测试

```
//直接调用SmallChangeSysOOP的对象，显示主菜单即可

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

}
}

```

![image-20240301133108586](https://oss.maolin101.com/202501070054999.png-101.webp)