java如何实现简单银行ATM系统

#ATM系统

##功能

模拟银行ATM机系统，具有注册、登录功能
用户登录后可实现以下功能：
1）存款 2）取款 3）转账 4）查询 5）退出

##设计思路

首先，要进行ATM机操作应该具有银行卡和ATM，所以我们要设计一个ATM类和Bankcard类，ATM具有存取款等操作，Bankcard用来记录用户存取款等操作后的越，其次因为ATM同时为多个用户服务，所以我们应该识别每张卡，这里增加一个Bank类来记录银行卡个数以及各个用户持有哪些银行卡。

##具体代码

###Bank类

import java.util.Arrays;

/**
 * @author:zl
 * @Date 22:30 2020/10/9
 */
 
public class Bank {
    private BankCard[] cards;
    private int size;// 有效用户个数
    private static final int INITSIZE  =10;
    public Bank(){
        this(INITSIZE);
    }
    public Bank(int num){
        cards = new BankCard[num];
    }
    public boolean add(BankCard card){//如果注册过，增加失败
        if(contains(card.getID(),card.getPasswd())!=null){
            return false;
        }
        if(size==cards.length){
            cards= Arrays.copyOf(cards,cards.length>>1);//长度不够时进行扩容
        }
        cards[size++] = card;//
        return true;
    }
    public boolean search(int id,int passwd){//查询是否存在这张卡
        boolean k=true;
        for(int i=0;i
###Bankcard类
import java.util.Scanner;

public class BankCard {
    private int id;
    private int passwd;
    public int money=0;
    public  BankCard(int id,int passwd){
        this.id=id;
        this.passwd=passwd;
    }
    public int getID(){
        return this.id;
    }
    public int getPasswd(){
        return this.passwd;
    }
    /**
     * 存款
     */
    public void saveMoney(int money){
       this.money+=money;
    }
    /**
     * 取款
     */
    public boolean withDraw(int money){
        boolean flag=false;
       if(this.money>=money){
           this.money-=money;
           flag=true;
       }
            return flag;
    }
    /**
     * 返回余额
     * @return
     */
    public int  getMoney(){
        return this.money;
    }
}
###ATM类
import java.util.Scanner;
import src3.BankCard;

public class ATM {
    private Bank bank;
    private static Scanner scanner;
    public ATM(){
        bank = new Bank();
        scanner = new Scanner(System.in);
    }

    public void start(){
        while (true) {
            System.out.println("1. 登陆 2.注册 3.关机");
            int chioce = scanner.nextInt();
            if (chioce == 3) {
                break;
            }
            System.out.println("请输入账号密码");
            int id = scanner.nextInt();
            int passwd = scanner.nextInt();
            BankCard successCard = null;
            switch (chioce){
                case 1:
                    successCard = login(id,passwd);
                    if(successCard != null){
                        System.out.println("登陆成功");
                        loginSuccess(successCard);
                    }else{
                        System.out.println("登陆失败");
                    }
                    break;
                case 2:
                    if(regiter(id,passwd)){
                        System.out.println("注册成功");
                    }else{
                        System.out.println("注册失败");
                    }
                    break;
            }
        }
    }
    private void loginSuccess(BankCard successCard){
        while (true) {
            System.out.println("1. 存款 2.取款 3.转账 4.余额 5.退卡");
            int chioce = scanner.nextInt();
            if (chioce == 5) {
                break;
            }
            switch (chioce) {
                case 1:
                    System.out.println("请输入存款金额");
                    int money = scanner.nextInt();
                    successCard.saveMoney(money);
                    System.out.println("存款成功");
                    break;
                case 2:
                    System.out.println("请输入取款金额");
                    money = scanner.nextInt();
                    if (successCard.withDraw(money)) {
                        System.out.println("取款成功");
                    } else {
                        System.out.println("取款失败");
                    }
                    break;
                case 3:
                    System.out.println("请输入转账金额");
                    money = scanner.nextInt();
                    System.out.println("请输入转账用户账号，密码");
                    int id = scanner.nextInt();
                    int passwd = scanner.nextInt();
                    BankCard userCard = bank.contains(id, passwd);
                    if (userCard != null) {
                        if (successCard.withDraw(money)) {// 当前卡取款成功
                            userCard.saveMoney(money);
                            System.out.println("转账成功");
                        } else {
                            System.out.println("余额不足");
                        }
                    } else {
                        System.out.println("没有此用户");
                    }
                    break;
                case 4:
                    System.out.println("余额：" + successCard.getMoney());
                    break;
            }
        }
    }

    private boolean regiter(int id,int passwd){
        BankCard card = new BankCard(id,passwd);
        return bank.add(card);
    }
    private BankCard login(int id,int passwd){
        return bank.contains(id,passwd);
    }
}
###测试类
public class TestDemo {
    public static void main(String[] args) {
        ATM atm = new ATM();
        atm.start();
    }
}