本文介紹了Java經典案例題供小白編程愛好者借鑒，因為我也是學習者，這是我的一點編程經驗和心得，如有錯誤，請指出，廢話不多說，開始步入正題，（ps:創作不易，有喜歡的小伙伴請點贊支持，謝謝啦！）

一、所需知識

此系統要求掌握知識點大致如下：
1、掌握控制臺專案的開發流程
2、了解專案所需的技術
3、熟悉專案需實作的功能
3、掌握專案登陸注冊的功能實作
4、掌握專案余額的功能實作
5、掌握專案存款轉賬的功能實作
6、掌握專案分層實作

二、需求及技術

需求： ATM系統是一個基于JAVA SE的控制臺版本的綜合專案，具有登錄、注冊、余額、存款、退出以及轉賬功能，
技術：- JAVA基礎 - 面向物件 - 分層

三、代碼

分析：分層：物體類層-Jopo -----服務層-service------視圖層-view-------測驗-test
通俗點說，就是創建三個包對應上面三個層，以下就是下面三個包的具體代碼

1. 物體類：Account

/*
賬戶物體類
 */
public class Account {
    private String uname;   //用戶名
    private String pwd;     //密碼
    private int idcard;     //卡號
    private double blance; //余額

    public Account() {
    }

    public Account(String uname, String pwd, int idcard, double blance) {
        this.uname = uname;
        this.pwd = pwd;
        this.idcard = idcard;
        this.blance = blance;
    }

    public String getUname() {
        return uname;
    }

    public void setUname(String uname) {
        this.uname = uname;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    public int getIdcard() {
        return idcard;
    }

    public void setIdcard(int idcard) {
        this.idcard = idcard;
    }

    public double getBlance() {
        return blance;
    }

    public void setBlance(double blance) {
        this.blance = blance;
    }

    @Override
    public String toString() {
        return "Account{" +
                "uname='" + uname + '\'' +
                ", pwd='" + pwd + '\'' +
                ", idcard=" + idcard +
                ", blance=" + blance +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (o instanceof Account){
            if (((Account) o).getUname().equals(uname)){
                return true;
            }
            return false;
        }
        return false;
    }

    @Override
    public int hashCode() {
        return 0;
    }
}

2. 服務層：AccountService

import com.yb.item.jopo.Account;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Random;

/*
賬戶服務層、邏輯判斷
 */
public class AccountService {
    private static Account account = new Account();
    private static double b = 0;

    //資料存盤
    private static HashSet<Account> al = new HashSet<Account>();

    //注冊
    public static void register(Account accounts){
        boolean rs = al.add(accounts);
        if (rs){
            System.out.println("注冊成功");
            //生成一個隨機卡號
            int card = createCard();
            accounts.setIdcard(card);
            account = accounts;
            System.out.println(account);
        }else{
            System.out.println("注冊失敗");
        }
    }

    //登錄
    public static boolean login(Account account){
        Iterator<Account> iterator = al.iterator();
        while (iterator.hasNext()){
            Account next = iterator.next();
            if (account.getIdcard()==next.getIdcard()){
                if (account.getPwd().equals(next.getPwd())){
                    System.out.println("登錄成功");
                    account=next;
                    b = next.getBlance();
                    System.out.println(next);
                    return true;
                }else{
                    System.out.println("密碼錯誤...");
                    return false;
                }
            }
            if (account.getIdcard()==next.getIdcard()){
                System.out.println("卡號錯誤...");
                    return false;
            }
        }
        return false;
    }

    //存款
    public static void deposit(double money){
        if (money>0){
            b = account.getBlance()+money;
            account.setBlance(b);
        }else {
            System.out.println("你這給我卡Bug呢！！");
        }
    }

    //查詢余額
    public static void CheckBalance(){
        System.out.println("您的余額為:"+b);

    }

    //轉賬
    public static void carryOver(int id,double money){
        Iterator<Account> iterator = al.iterator();
        while (iterator.hasNext()){
            Account next = iterator.next();
            if (next.getIdcard()==id){
                if (money>account.getBlance()){
                    System.out.println("轉賬失敗...");
                }else{
                    //自己的錢減少
                    b=account.getBlance()-money;
                    account.setBlance(b);
                    //他的錢變多
                    b = next.getBlance()+money;
                    next.setBlance(b);
                }
                System.out.println("您轉入的賬戶："+next.getUname()+",余額為："+next.getBlance());
                //將賬戶重新賦值
                b = next.getBlance();

            }
        }
        System.out.println("您的賬戶余額為："+account.getBlance());
    }

    //取款
    public static void getMoney(double money){
        if (account.getBlance()>=money&&money>0&&account.getBlance()>=0){
            account.setBlance(account.getBlance()-money);
            System.out.println("取款成功，當前余額為："+account.getBlance());
        }else {
            System.out.println("取款失敗");
        }
    }



    //自動生成銀行卡號
    public static int createCard(){
        Random random = new Random();
        //可以追加判斷，如果重復生成，則重新生成一個隨機卡號
        int num = random.nextInt(100000000)+999999999;
        return num;
    }

}

3. 視圖層：AccountService

import com.yb.item.jopo.Account;
import com.yb.item.service.AccountService;

import java.util.Scanner;

public class AccountView {

    private static Scanner scanner = new Scanner(System.in);
    private static AccountService as  = new AccountService();
    private static AccountView av  = new AccountView();

        //選單
         public static void menu(String[] a){
             System.out.println("--------------------------------------------------------------");
                for (int i = 0; i <= a.length-1; i++) {
                    System.out.print((i+1)+","+a[i]+"  ");
                }
                System.out.println();
             System.out.println("--------------------------------------------------------------");
            }

         //獲取物件
         public static void getUser(){

         }


        //首頁
         public static void index(){
             //new String[]{"注冊","登錄","存款","余額","轉賬","取款","退出"}

             while (true) {
                 menu(new String[]{"注冊","登錄","退出"});
                 System.out.println("請輸入您的操作：");
                 int num = scanner.nextInt();
                 switch (num){
                     case 1:
                         //注冊
                         System.out.println("請輸入您的姓名：");
                         String username = scanner.next();
                         System.out.println("請輸入您的密碼：");
                         String password = scanner.next();
                         as.register(new Account(username,password,0,0));
                         break;
                     case 2:
                         //登錄
                         System.out.println("請輸入您的卡號：");
                         int id = scanner.nextInt();
                         System.out.println("請輸入您的密碼：");
                         String pwd = scanner.next();
                         boolean login = as.login(new Account("", pwd, id, 0));

                         while (login) {
                             menu(new String[]{"存款","余額","轉賬","取款","退出"});
                             System.out.println("請輸入您的操作：");
                             int i = scanner.nextInt();
                             switch (i) {
                                 case 1:
                                     //存款
                                     System.out.println("請輸入要存的金額：");
                                     double mon = scanner.nextDouble();
                                     as.deposit(mon);
                                     break;
                                 case 2:
                                     //查詢余額
                                     as.CheckBalance();
                                     break;
                                 case 3:
                                     //轉賬
                                     System.out.println("請輸入要轉入賬戶：");
                                     int id1 = scanner.nextInt();
                                     System.out.println("請輸入要轉入的金額：");
                                     double mon1 = scanner.nextDouble();
                                     as.carryOver(id1,mon1);

                                     break;
                                 case 4:
                                     //取款
                                     System.out.println("請輸入您要取出的金額：");
                                     double mon2 = scanner.nextDouble();
                                     as.getMoney(mon2);
                                     break;
                                 case 5:
                                     //退出
                                     login=false;
                             }
                         }
                         continue;
                     case 3:
                         System.exit(0);

                 }
             }

         }

}

4. 測驗類：Test

public static void main(String[] args) {

        av.index();


    }

5. 結果截圖

以上就是這個ATM取款系統的的整體流程，有喜歡的朋友可以幫忙點個贊，謝謝！