Java小玩意：模拟ATM

一、写在前面

本来是其他班的作业，原本是用来练习集合存储对象，正好最近学了JDBC，缺个小玩意练习，这不缺啥来啥吗，然后就写了这个小屎山😅

纯手写，欢迎指正。

二、功能介绍

注册&登录
存取款
查询
转账
修改信息

效果展示

三、基本逻辑

登录：获取输入的ID，到数据库中查询此ID的用户信息，查询成功则创建此用户对象，否则提示错误
注册：用户需要输入用户名，性别，登录密码等信息，然后自动生成ID，然后将用户信息存储到数据库中
存取款：用户输入需要存取的金额，在此对象对应的“余额”属性中对应增加或减少相应数额，然后再更新数据库
转账：用户输入转向的ID后，在数据库中查询此ID对应的用户信息，查询成功则创建此用户对象没否则提示错误。输入转账金额后，两个用户对象的“余额”属性同时增加和减少转账的数额，然后更新数据库
修改信息：将此用户对象的属性更改后，更新数据库。

四、数据库结构

CREATE TABLE `account` (
  `uid` varchar(18) COLLATE utf8mb4_general_ci NOT NULL,
  `userName` varchar(10) COLLATE utf8mb4_general_ci NOT NULL,
  `passwd` varchar(12) COLLATE utf8mb4_general_ci NOT NULL,
  `balance` double DEFAULT NULL,
  `xianE` double DEFAULT NULL,
  `gender` varchar(2) COLLATE utf8mb4_general_ci NOT NULL,
  PRIMARY KEY (`uid`)
)

五、关键代码

public void createAccount() throws SQLException {
    Account account = new Account();
    account.createName();
    account.createGender();
    account.createPasswd();
    account.createBalance();
    account.createXianE();
    // 随机生成3个3位数字
    Random ran = new Random();
    int ID1 = ran.nextInt(100, 1000);
    int ID2 = ran.nextInt(100, 1000);
    int ID3 = ran.nextInt(100, 1000);
    String ID = "" + ID1 + ID2 + ID3;
    Integer uID = Integer.parseInt(ID);
    account.setuID(uID);
    Connection conn;
    {
        try {
            conn = DriverManager.getConnection(url, user, password);
            PreparedStatement ps;
            {
                try {
                    String sql = "insert into account (uid,userName,gender, passwd, balance, xianE) values ( ?,?, ?, ?, ?, ?)";
                    ps = conn.prepareStatement(sql);
                    ps.setString(1, String.valueOf(account.getuID()));
                    ps.setString(2, account.getUserName());
                    ps.setString(3, account.getGender());
                    ps.setString(4, account.getPasswd());
                    ps.setDouble(5, account.getBalance());
                    ps.setDouble(6, account.getXianE());
                    ps.executeUpdate();
                }; catch (SQLException e) {
                    throw new RuntimeException(e);
                };
                try {
                    ps.close();
                    conn.close();
                }; catch (SQLException e) {
                    throw new RuntimeException(e);
                };
            };
        }; catch (SQLException e) {
            throw new RuntimeException(e);
        };
    };
    System.out.println("注册成功！");
    System.out.println(account);
    System.out.println("即将返回主界面...");
};

public Account login() {
        Account account = new Account();
        String[] userInfo;
        System.out.println("请输入您的ID：");
        int uID = new Scanner(System.in).nextInt();
        // 接收用户输入后去数据库里查询信息
        JDBC jdbc = new JDBC();
        String sql = "select * from account where uid = " + uID;
        try {
            // 将查询到的用户信息保存到userInfo中
            userInfo = jdbc.getUserInfo(sql);
            if (userInfo == null) {
                System.out.println("无此用户，请重新输入");
                account = login();
            }; else {
                // 密码认证
                boolean autFlag = autPasswd(userInfo);
                for (int i = 0; true; i++) {
                    // 若认证密码返回true，将查询到的信息赋给account对象
                    if (autFlag) {
                        account.setuID(Integer.parseInt(userInfo[0]));
                        account.setUserName(userInfo[1]);
                        account.setPasswd(userInfo[2]);
                        account.setBalance(Double.parseDouble(userInfo[3]));
                        account.setXianE(Double.parseDouble(userInfo[4]));
                        account.setGender(userInfo[5]);
                        System.out.println("登录成功...");
                        break;
                    }; else {
                        System.out.println("密码错误，请重新输入!");
                        System.out.println("您还有" + (2 - i) + "次机会");
                        autFlag = autPasswd(userInfo);
                    };
                    if (i == 2) {
                        System.out.println("密码错误次数过多，程序退出，感谢您的使用！");
                        System.exit(0);
                    };
                };
            };
        }; catch (SQLException e) {
            throw new RuntimeException(e);
        };
        return account;
    };

登录成功后显示菜单

public void showMenu(Account account) {
    if (this.getGender().equals("男")) {
        System.out.println("您好，" + account.getUserName() + "先生，欢迎使用ATM机！");
    }; else if (this.getGender().equals("女")) {
        System.out.println("您好，" + account.getUserName() + "女士，欢迎使用ATM机！");
    }; else {
        System.out.println("您好，" + account.getUserName() + "，欢迎使用ATM机！");
    };
    System.out.println("请选择您要进行的操作：");
    System.out.println("1.存款");
    System.out.println("2.取款");
    System.out.println("3.转账");
    System.out.println("4.查询余额");
    System.out.println("5.修改账户信息");
    System.out.println("6.退出");
    Scanner scanner = new Scanner(System.in);
    int choice = scanner.nextInt();
};

这里会根据用户信息显示“某某先生”还是”某某女士“；

转账

public void transferMoney(Account account) {
        Account transferAccount = new Account();
        System.out.println("请输入您要转账的账户ID：");
        int uID = new Scanner(System.in).nextInt();
        String[] transferUserInfo;
        JDBC jdbc = new JDBC();
        String sql = "select * from account where uid = " + uID;
        try {
            transferUserInfo = jdbc.getUserInfo(sql);
            if (transferUserInfo == null) {
                System.out.println("无此用户，请重新输入");
                transferMoney(account);
            }; else {
                transferAccount.setuID(Integer.parseInt(transferUserInfo[0]));
                transferAccount.setUserName(transferUserInfo[1]);
                transferAccount.setPasswd(transferUserInfo[2]);
                transferAccount.setBalance(Double.parseDouble(transferUserInfo[3]));
                transferAccount.setXianE(Double.parseDouble(transferUserInfo[4]));
            };
        }; catch (SQLException e) {
            throw new RuntimeException(e);
        };
        System.out.println("请确认您要转账的账户信息：");
        System.out.println("账户ID：" + transferAccount.getuID());
        System.out.println("用户名：" + transferAccount.getUserName());
        System.out.println("请输入您要转账的金额：");
        double money = new Scanner(System.in).nextDouble();
        double thisBalance = account.getBalance();
        double thatBalance = transferAccount.getBalance();
        thisBalance -= money;
        thatBalance += money;
        account.setBalance(thisBalance);
        transferAccount.setBalance(thatBalance);
        sql = "update account set balance = " + thisBalance + " where uid = " + account.getuID();
        jdbc.update(sql);
        sql = "update account set balance = " + thatBalance + " where uid = " + transferAccount.getuID();
        jdbc.update(sql);
        System.out.println("转账成功，您的余额为：" + thisBalance);
        showMenu(account);
    };

修改信息

private void updateAccount(Account account) {
        JDBC jdbc = new JDBC();
        System.out.println("更新账户信息：");
        System.out.println(account.getUserName());
        System.out.println(account.getPasswd());
        System.out.println(account.getXianE());
        System.out.println("请输入您要更新的信息：");
        System.out.println("1.用户名");
        System.out.println("2.密码");
        System.out.println("3.取款限额");
        System.out.println("4.返回上级菜单");
        Scanner scanner = new Scanner(System.in);
        int choice = scanner.nextInt();
        switch (choice) {
            case 1:
                System.out.println("请输入您的新用户名：");
                String newUserName = scanner.next();
                account.setUserName(newUserName);
                String sql = "update account set username = '" + account.getUserName() + "' where uid = " + account.getuID();
                jdbc.update(sql);
                System.out.println("更新成功！");
                updateAccount(account);
                break;
            case 2:
                System.out.println("请输入您的新密码：");
                String newPasswd = scanner.next();
                account.setPasswd(newPasswd);
                String sql1 = "update account set passwd = '" + account.getPasswd() + "' where uid = " + account.getuID();
                jdbc.update(sql1);
                System.out.println("更新成功！");
                updateAccount(account);
                break;
            case 3:
                System.out.println("请输入您的新取款限额：");
                double newXianE = scanner.nextDouble();
                account.setXianE(newXianE);
                String sql2 = "update account set xiane = " + account.getXianE() + " where uid = " + account.getuID();
                jdbc.update(sql2);
                System.out.println("更新成功！");
                updateAccount(account);
                break;
            case 4:
                showMenu(account);
                break;
            default:
                System.out.println("输入错误，请重新输入！");
                updateAccount(account);
                break;
        };
    };