Java实战案例———

需求分析

首先ATM银行系统包括两个基础大功能：开户和登陆账户（当然在系统中没有一个账户时不能登录，需要先开户）。

一名用户有6项基本信息描述：姓名、性别、银行卡号、银行卡密码、账户余额、取款限额。

在登录账户后又有7项功能：查询账户信息、存款、取款、转账、修改密码、退出、注销账户。

代码展示

// ATM.java

public class ATM {
    private int id;
    private String name;
    private char sex;
    private double moneyLeft;
    private double moneyCon;
    private String code;

    public ATM() {}

    public ATM(int id, String name, char sex, double moneyLeft, double moneyCon, String code) {
        this.id = id;
        this.name = name;
        this.sex = sex;
        this.moneyLeft = moneyLeft;
        this.moneyCon = moneyCon;
        this.code = code;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public char getSex() {
        return sex;
    }

    public void setSex(char sex) {
        this.sex = sex;
    }

    public double getMoneyLeft() {
        return moneyLeft;
    }

    public void setMoneyLeft(double moneyLeft) {
        this.moneyLeft = moneyLeft;
    }

    public double getMoneyCon() {
        return moneyCon;
    }

    public void setMoneyCon(double moneyCon) {
        this.moneyCon = moneyCon;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }
}

// ATMOperator.java

public class ATMOperator {
    ArrayList<ATM> ATMlist = new ArrayList<>();

    //开户
    public void register() {
        ATM user = new ATM();
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入你的用户名");
        String name = sc.next();
        user.setName(name);
        while (true) {
            System.out.println("请输入你的性别，‘男’ 或 ‘女’ ");
            String tmp = sc.next();
            char sex = tmp.charAt(0);
            if (sex != '男' && sex != '女') {
                System.out.println("请输入‘男’ 或 ‘女’");
            } else {
                user.setSex(sex);
                break;
            }
        }
        while (true) {
            System.out.println("请输入你的密码");
            String code = sc.next();
            System.out.println("请确认你的密码");
            String confirmCode = sc.next();
            if (code.equals(confirmCode)) {
                user.setCode(code);
                break;
            } else {
                System.out.println("两次密码不一致，请重新输入密码");
            }
        }
        System.out.println("请输入你的每次取款限额");
        double moneyCon = sc.nextDouble();
        user.setMoneyCon(moneyCon);

        String id = "";
        Random r = new Random();
        for (int i = 0; i < 7; i++) {
            int num = r.nextInt(10);
            id += num;
        }
        System.out.println("恭喜你，开户成功！卡号是：" + id);
        int id1 = Integer.parseInt(id);
        user.setId(id1);

        ATMlist.add(user);
    }

    //查询打印账户信息
    public void print(int n) {
        System.out.println("----------" + ATMlist.get(n).getName() + "先生的账户信息----------");
        System.out.println("账户卡号：" + ATMlist.get(n).getId());
        System.out.println("账户名：" + ATMlist.get(n).getName());
        System.out.println("性别：" + ATMlist.get(n).getSex());
        System.out.println("余额：" + ATMlist.get(n).getMoneyLeft());
        System.out.println("取款限额：" + ATMlist.get(n).getMoneyCon());
        System.out.println("--------------------------------");
    }

    //展示登录界面
    public void showLogon(int user) {
        Scanner sc = new Scanner(System.in);
        while (true) {
            System.out.println("请输入你需要办理的业务号");
            System.out.println("1、查询打印账户信息");
            System.out.println("2、存款");
            System.out.println("3、取款");
            System.out.println("4、转账");
            System.out.println("5、修改密码");
            System.out.println("6、退出");
            System.out.println("7、注销账户");
            String n = sc.next();
            switch (n) {
                case "1":
                    print(user);
                    break;
                case "2":
                    saveMoney(user);
                    break;
                case "3":
                    getMoney(user);
                    break;
                case "4":
                    transforAccounts(user);
                    break;
                case "5":
                    changePassword(user);
                    break;
                case "6":
                    return;
                case "7":
                    unsubscribe(user);
                    break;
                default:
                    System.out.println("请输入正确的指令");
                    break;
            }
        }
    }


    //登录账户
    public int logon() {
        if (ATMlist.size() == 0) {
            System.out.println("您还未开户，请先开户");
            throw new RuntimeException("Exception occurred");
        }
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入你的卡号");
        int id = sc.nextInt();
        int tmp = -1;
        for (int i = 0; i < ATMlist.size(); i++) {
            if (ATMlist.get(i).getId() == id) {
                System.out.println(ATMlist.get(i).getName() + "先生，您已经成功登录账户");
                tmp = i;
                break;
            }
        }
        if (tmp == -1) {
            System.out.println("您输入的卡号不存在");
            throw new RuntimeException("Exception occurred");
        } else {
            showLogon(tmp);
            return tmp;
        }
    }

    //存款
    public void saveMoney(int user) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入你要存的金额");
        double saveMoney = sc.nextDouble();
        double rs = saveMoney + ATMlist.get(user).getMoneyLeft();
        System.out.println("存钱成功！您的余额为：" + rs);
        ATMlist.get(user).setMoneyLeft(rs);
    }

    //取款
    public void getMoney(int user) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入你要取的金额");
        double money = sc.nextDouble();
        if (money > ATMlist.get(user).getMoneyLeft()) {
            System.out.println("余额不足，取款失败");
        } else {
            double rs = ATMlist.get(user).getMoneyLeft() - money;
            ATMlist.get(user).setMoneyLeft(rs);
            System.out.println("取款成功！你的余额为：" + ATMlist.get(user).getMoneyLeft());
        }
    }

    //转账
    public void transforAccounts(int user) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入你的转账对象的卡号");
        int id = sc.nextInt();
        for (int i = 0; i < ATMlist.size(); i++) {
            if (id == ATMlist.get(i).getId()) {
                System.out.println("请问是要给*" + ATMlist.get(i).getName().substring(1) + "转账吗？");
                String tmp = sc.next();
                char answer = tmp.charAt(0);
                if (answer == (ATMlist.get(i).getName().charAt(0))) {
                    System.out.println("请输入你要转账的金额");
                    double money = sc.nextDouble();
                    if (money > ATMlist.get(user).getMoneyLeft()) {
                        System.out.println("你的余额不足，转账失败");
                        return;
                    } else {
                        if (money > ATMlist.get(user).getMoneyCon()) {
                            System.out.println("超出取款限额，请重试");
                            return;
                        } else {
                            double rs = ATMlist.get(user).getMoneyLeft() - money;
                            ATMlist.get(user).setMoneyLeft(rs);
                            double otherrs = ATMlist.get(i).getMoneyLeft() + money;
                            ATMlist.get(i).setMoneyLeft(otherrs);
                            System.out.println("转账成功！您的余额为：" + rs);
                        }
                    }
                } else {
                    System.out.println("你输入的对方账户姓氏不正确，请重试");
                    return;
                }
            }else System.out.println("卡号输入有误，请重试");
        }
    }

    //修改密码
    public void changePassword(int user) {
        Scanner sc = new Scanner(System.in);
        System.out.println("确认为本人，请输入你的新密码");
        String newcode = sc.next();
        System.out.println("请确认新密码");
        String confirmCode = sc.next();
        if (newcode.equals(confirmCode)) {
            ATMlist.get(user).setCode(newcode);
            System.out.println("修改密码成功！请牢记密码");
        } else {
            System.out.println("两次密码不一致，请重试");
            return;
        }
    }

    //退出
    public void exit() {
        ;
    }

    //注销账户
    public void unsubscribe(int user) {
        Scanner sc = new Scanner(System.in);
        while (true) {
            System.out.println("你确定要注销该账户？y/n");
            String answer = sc.next();
            if (answer.equals("y")) {
                System.out.println("你已成功注销账户");
                ATMlist.remove(user);
                break;
            } else if (answer.equals("n")) {
                System.out.println("你选择了保留账户");
                break;
            } else {
                System.out.println("请输入 y/n");
            }
        }
    }

    public void start() {
        Scanner sc = new Scanner(System.in);
        while (true){
            System.out.println("请选择你要进行的操作");
            System.out.println(("1、开户"));
            System.out.println("2、登录账户");
            System.out.println("0、退出系统");
            String num = sc.next();
            switch (num) {
                case "0":
                    return;
                case "1":
                    register();
                    break;
                case "2":
                    int user = logon();
                    break;
                default:
                    System.out.println("请输入正确的指令");
                    break;
            }
        }
    }
}

// Test.java (测试用例)

public class Test {
    public static void main(String[] args) {
        ATMOperator ts = new ATMOperator();
        ts.start();
    }
}