通过使用Java面向对象的基础知识，开发一个ATM系统，实现存款，取款，转账，修改密码，注销账户等功能。
首先，创建一个用户类，为建立用户对象做准备，用户类主要包括用户卡号（系统随机生成），用户名，账户密码，余额，取现额度。并搭建构造器，以及get,set。
public class user {
private String cardId ; //卡号
private String username; //用户名
private String password; //密码
private double money; //余额
private double qumoney; //取现额度
public user(String cardId, String username, String password, double qumoney) {
this.cardId = cardId;
this.username = username;
this.password = password;
this.qumoney = qumoney;
}
public user() {
}
public String getCardId() {
return cardId;
}
public void setCardId(String cardId) {
this.cardId = cardId;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public double getMoney() {
return money;
}
public void setMoney(double money) {
this.money = money;
}
public double getQumoney() {
return qumoney;
}
public void setQumoney(double qumoney) {
this.qumoney = qumoney;
}
}public class ATMSystem {
public static void main(String[] args) {
ArrayList<user> users = new ArrayList<>();
Main(users);
}public static void Main(ArrayList<user> users) {
System.out.println("==========欢迎进入xx银行ATM系统==========");
while (true) {
System.out.println("请选择操作:");
System.out.println("1.登录账户");
System.out.println("2.注册账户");
Scanner sc = new Scanner(System.in);
int command = sc.nextInt();
switch (command) {
case 1: //登录
denglu(users, sc);
break;
case 2: //注册
zhuce(users, sc);
break;
default:
System.out.println("功能不存在！");
}
}
}运行结果：
public static void zhuce(ArrayList<user> users, Scanner sc) {
System.out.println("==========注册账户==========");
String password = "";
String password2 = "";
System.out.println("请输入您的账号名称:");
sc = new Scanner(System.in);
String name = sc.next();
while (true) {
System.out.println("请输入您的账号密码:");
password = sc.next();
System.out.println("请您再次输入密码:");
password2 = sc.next();
if (password2.equals(password)) {
break;
} else {
System.out.println("两次密码输入不一致！,请重新输入");
}
}
//生成卡号
System.out.println("请输入账号当次限额");
double qumoney = sc.nextDouble();
String cardId = kahao(users);
user u1 = new user(cardId, name, password, qumoney);
users.add(u1);
System.out.println("恭喜开户成功！,您的卡号是" + u1.getCardId() + "，请您保管");
}其中，涉及到生成卡号，以及查询系统生成的卡号是否相同，需要再写两个方法：
//生成卡号
public static String kahao(ArrayList<user> users) {
while (true) {
Random rs = new Random();
String cardId = "";
for (int i = 0; i < 8; i++) {
cardId += rs.nextInt(10);
}
user a = getcardId(cardId, users);
if (a == null) {
//无重复
return cardId;
}
}
}//查询卡号
public static user getcardId(String kahao, ArrayList<user> users) {
for (int i = 0; i < users.size(); i++) {
user a = users.get(i);
if (a.getCardId().equals(kahao)) {
return a;
}
}
return null;
}public static void denglu(ArrayList<user> users, Scanner sc) {
System.out.println("==========登录账户==========");
if (users.size() == 0) {
System.out.println("系统中无账户！请先注册");
return;
}
while (true) {
System.out.println("请输入您的卡号:");
String cardId = sc.next();
String password = "";
user acc = getcardId(cardId, users);
if (acc != null) {
while (true) {
System.out.println("请输入您的密码:");
password = sc.next();
//判断密码是否正确
if (acc.getPassword().equals(password)) {
System.out.println("登录成功！,欢迎卡号" + acc.getCardId() + "的贵宾" + acc.getUsername() + "进入系统");
//展示系统登录后的操作界面
jiemian(sc, acc, users);
return;
} else {
System.out.println("密码错误！请重新输入");
}
}
} else {
System.out.println("不存在该卡号！");
}
}
}六.1编写 展示主界面方法
public static void jiemian(Scanner sc, user acc, ArrayList<user> users) {
while (true) {
System.out.println("==========欢迎进入xx银行用户操作界面===========");
System.out.println("请您输入操作命令:");
System.out.println("1.查询:");
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.注销当前账户");
sc = new Scanner(System.in);
int commend = sc.nextInt();
switch (commend) {
case 1:
atm1(acc);
break;
case 2:
atm2(acc, sc);
break;
case 3:
atm3(acc, sc);
break;
case 4:
atm4(users, acc, sc);
break;
case 5:
atm5(acc, sc);
return;
case 6:
System.out.println("欢迎下次来到ATM系统");
return;
case 7:
System.out.println("是否确认注销账户？按1确认，按2取消注销");
int tf = sc.nextInt();
if (tf == 1) {
users.remove(acc);
System.out.println("注销成功！");
return;
} else {
System.out.println("取消注销");
break;
}
default:
System.out.println("不存在该功能！");
}
}
}//查询功能
private static void atm1(user acc) {
System.out.println("========当前账户详情=========");
System.out.println("卡号:" + acc.getCardId());
System.out.println("姓名:" + acc.getUsername());
System.out.println("余额:" + acc.getMoney());
System.out.println("当次取款限额:" + acc.getQumoney());
}
//存款功能
private static void atm2(user acc, Scanner sc) {
System.out.println("=========存款操作=========");
System.out.println("请您输入存款金额：");
double money = sc.nextDouble();
acc.setMoney(acc.getMoney() + money);
System.out.println("存款成功！");
atm1(acc);
}
//取款
private static void atm3(user acc, Scanner sc) {
System.out.println("=========取款操作=========");
if (acc.getMoney() < 100) {
System.out.println("您的账户余额不足100元！无法取款");
return;
} else {
while (true) {
System.out.println("请您输入取款金额:");
double money = sc.nextDouble();
if (money > acc.getMoney()) {
System.out.println("账户余额不足！");
System.out.println("继续取款按1，退出取款按2");
int commend = sc.nextInt();
switch (commend) {
case 1:
break;
case 2:
return;
}
} else if (money > acc.getQumoney()) {
System.out.println("超过了当次取款限额！,每次最多可以取" + acc.getQumoney() + "元");
} else {
System.out.println("取款成功！");
acc.setMoney(acc.getMoney() - money);
atm1(acc);
return;
}
}
}
}
//转账
private static void atm4(ArrayList<user> users, user acc, Scanner sc) {
System.out.println("=========转账操作=========");
//判断系统中是否有两个以上账户
if (users.size() < 2) {
System.out.println("系统中无其他账户，不可以转账！");
return;
} else {
if (acc.getMoney() == 0) {
System.out.println("您的账户余额为0，无法转账");
return;
} else {
while (true) {
System.out.println("请输入对方的卡号：");
String dui = sc.next();
user c = getcardId(dui, users);
if (c != null) {
//判断账户对象是否为自己
if (c.getCardId().equals(acc.getCardId())) {
System.out.println("不能给自己转账！");
} else {
//确认对方姓氏
String name = "*" + c.getUsername().substring(1);
System.out.println("请您确认[" + name + "]的姓氏");
String xingshi = sc.next();
if (c.getUsername().startsWith(xingshi)) {
System.out.println("输入正确！");
while (true) {
System.out.println("请您输入转账金额：");
double money = sc.nextDouble();
if (money > acc.getMoney()) {
System.out.println("余额不足！");
System.out.println("继续转账按1，退出转账按2");
int commend = sc.nextInt();
switch (commend) {
case 1:
break;
case 2:
return;
}
} else {
acc.setMoney(acc.getMoney() - money);
c.setMoney(c.getMoney() + money);
System.out.println("为" + c.getUsername() + "用户" + "转账成功");
atm1(acc);
return;
}
}
} else {
System.out.println("对不起，您输入的信息有误！");
}
}
} else {
System.out.println("对不起，您输入卡号有误！");
}
}
}
}
}
//修改密码操作
private static void atm5(user acc, Scanner sc) {
System.out.println("=========修改密码操作=========");
while (true) {
System.out.println("请输入您的旧密码:");
String oldpassword = sc.next();
String newpassword = "";
if (oldpassword.equals(acc.getPassword())) {
while (true) {
System.out.println("请输入新密码：");
newpassword = sc.next();
if (newpassword.equals(oldpassword)) {
System.out.println("新密码不能与旧密码重复！");
} else {
System.out.println("请再次输入密码:");
String okpassword = sc.next();
if (newpassword.equals(okpassword)) {
System.out.println("修改密码成功！");
acc.setPassword(newpassword);
return;
} else {
System.out.println("两次密码输入不一致！");
}
}
}
}
else{
System.out.println("旧密码输入错误！");
}
}
}至此，所有功能完成。
