Question

关于用JAVA编程ATM模拟程序问题

ATM柜员机模拟程序
要求：使用图形用户界面。当输入给定的卡号和密码（初始卡号和密码为123456）时，系统能登录ATM柜员机系统，用户可以按照以下规则进行：
(1)查询余额功能：初始余额为3000元
(2)ATM取款功能：每次取款金额为100的倍数，总额不超过2000元，支取金额不允许透支。
(3)ATM存款功能：不能出现负存款。
(4)修改密码：新密码长度不小于4位，不允许出现4位完全相同的情况，只有旧密码正确，新密码符合要求，且两次输入相同的情况下才可以成功修改密码。
急~~~
邮箱是wangman456@126.com 谢谢啦~

Answer 1

/*
要求：使用字符用户界面。当输入给定的卡号和密码（初始卡号和密码为123456）时，系统能登录ATM柜员机系统，用户可以按照以下规则进行：
1、查询余额：初始余额为10000元
2、ATM取款：每次取款金额为100的倍数，总额不超过5000元，支取金额不允许透支。
3、ATM存款：不能出现负存款。
4、修改密码：新密码长度不小于6位，不允许出现6位完全相同的情况，只有旧密码正确，新密码符合要求，且两次输入相同的情况下才可以成功修改密码。
（卡号密码余额放到文件中）
*/

public class ATM {

private Account acc;

private File dataFile;
private FileWriter fw;
private BufferedWriter bw;

private String filePath = "./data.txt";

public ATM() {
this.acc = new Account();
try {
this.dataFile = new File(this.filePath);
if (!this.dataFile.exists()) {
this.dataFile.createNewFile();
}
this.fw = new FileWriter(this.filePath);
this.bw = new BufferedWriter(this.fw);
} catch (IOException io) {
System.err.println("Cannot open file");
io.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}

public static void main(String[] args) {
new ATM().interact();
}

public void interact() {

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Account #: ");
String temp = br.readLine();
System.out.println("Password: ");
String temp2 = br.readLine();
if (!this.acc.isValid(Long.parseLong(temp.trim()), temp2.trim()) {
System.err.println("Wrong password");
return;
}
System.out.println("1. Account Inquery.");
System.out.println("2. Withdraw");
System.out.println("3. Deposit.");
System.out.println("4. Change Password.");
System.out.println("5. Export to File.");
System.out.println("0. Exit.");
int c = 100;
while (c != 0) {
String str = br.readLine();
try {
int c = Integer.parseInt(str.trim());
} catch (NumberFormatException nfe) {
System.err.println("Invalid choice");
continue;
}
switch (c) {
case 0:
System.out.println("Thank you");
break;
case 1:
System.out.println("Balance: " + this.acc.balanceInquery());
break;
case 2:
System.out.println("How much? ");
String temp = br.readLine();
try {
long ammount = Long.parseLong(temp.trim());
this.acc.withdraw(ammount);
break;
} catch (NumberFormatException nfe) {
System.err.println("Invalid amount");
continue;
}
case 3:
System.out.println("How much? ");
String temp = br.readLine();
try {
long ammount = Long.parseLong(temp.trim());
this.acc.deposit(ammount);
break;
} catch (NumberFormatException nfe) {
System.err.println("Invalid amount");
continue;
}
case 4:
System.out.println("Old password: ");
String temp = br.readLine();
System.out.println("New password: ");
String temp2 = br.readLine();
this.acc.changePassword(temp, temp2);
break;
case 5:
this.bw.write(this.acc.toString());
break;
default:
break;
}
}
}

}

class Account {

private long accNo = 123456;
private String pass = "123456";
private long balance = 10000;

public Account() {

}

public boolean isValid(long accNo, String pass) {
return (this.accNo == accNo) && (pass.equals(this.pass));
}

public void changePassword(String oldPass, String password) {
if (!oldPass.equals(this.pass)) {
System.err.println("Wrong password.");
return;
}
if (password.length < 6) {
System.err.println("Password too short");
return;
}
if (password.equals(this.pass)) {
System.err.println("Password cannot be the same.");
return;
}
this.pass = password;
}

public long balanceInquery() {
return this.balance;
}

public void withdraw(long amount) {
if (amount > 5000 || amount < 0) {
System.err.println("Withdraw limit: $0-$5000");
return;
}
if ((amount % 100) != 0) {
System.err.println("The amount has to be a product of 100");
return;
}
long newBalance = this.balance - amount;
if (newBalance < 0) {
System.err.println("Not enough money in the account");
return;
}
this.balance = newBalance;
}

public void deposit(long amount) {
if (amount < 0) {
System.err.println("Cannot deposit negative amount");
return;
}
this.balance += amount;
}

public String toString() {
return ("Account #: " + this.accNo + "\n" + "Password: " + this.pass + "\n" + "Balance: " + this.balance);
}
}