java ATM用于3个账户，每个账户有3个密码，一旦转账就看不到以前的余额
我有一个3个账户的ATM项目，每个账户都有一个单独的密码，问题是余额一旦我换了账户，例如我从账户a转账到账户b，转账后我看不到我以前的余额，我只能看到我转账的账户的余额
/**
* Class to implement the ATM (in OOP),support
* 1.deposit
* 2.withdraw
* 3.transfer
* 4.display balance
*/
public final class Atm02 {
// declaring variable
private int service;
private double balance;
private double amount;
private String account;
private String password;
private String destinationAccount;
static Scanner console = new Scanner(System.in);
/**
* default constructor
*
* @throws FileNotFoundException
*/
public Atm02() throws FileNotFoundException {
printWlecome();
inputAccount();
if (isSuccessfullLogin());
do {
selectService();
provideService();
} while (this.service != 0);
printGoodbye();
}
/**
* default constructor
*
* @param newService
* @param newBalance
* @param newAmount
*/
public Atm02(int newService, double newBalance, double newAmount) {
this.service = newService;
this.balance = newBalance;
this.amount = newAmount;
}
/**
* method to ask account number from the user
*
*/
public void inputAccount() {
System.out.print("Please enter your account:");
this.account = console.next();
}
/**
* method to ask the password from the user
*/
public void inputPassword() {
System.out.print("Please enter your password:");
this.password = console.next();
}
/**
* method to check the user and his password of the account
*
* @return true if user and password match
* @throws FileNotFoundException
*/
public boolean isSuccessfullLogin() throws FileNotFoundException {
String savedAccount;
String savedPassword;
final int MAX_TRIES = 3;
// load the user.txt we need loop to match the right account
//load the user.txt
Scanner inFile = new Scanner(new FileReader("user.txt"));
// to find the user and password of this account
do {
savedAccount = inFile.next();
savedPassword = inFile.next();
} while (!savedAccount.equals(this.account));
inFile.close();
// compare with the account password
for (int i = 1; i <= MAX_TRIES; i++) {
// input the password
inputPassword();
if (this.password.equals(savedPassword))
return true;
else
System.out.println("The password is wrong.");
}
System.out.printf("You input password %d times wrong.%n", MAX_TRIES);
return false;
}
/**
* method to print Welcome message
*
*/
public void printWlecome() {
System.out.println("Welcom to the TD ATM");
}
/**
* method to print good bye
*/
public void printGoodbye() {
System.out.println("Goodbye thank you for using TD BANK ATM. ");
}
/**
* method to print menu for all the services
*/
public void printMenu() {
System.out.println("Please select the service");
System.out.println("1. Deposit ");
System.out.println("2. Withdraw ");
System.out.println("3. Transfer ");
System.out.println("4. Display the current balance ");
System.out.println("0. Quit ");
System.out.println("Your choice is: ");
}
/**
* Method to check if the user selected service is valid, if not please ask
* user to select service again until valid
*
*/
public void checkServiceValid() {
while (this.service < 0 || this.service > 4) {
System.out.println("Invalid service");
printMenu();
this.service = console.nextInt();
}
}
/**
* Method ask the user select the service and check if the service is valid
*/
public void selectService() {
// ask the user to select the service
printMenu();
this.service = console.nextInt();
// check if the servicce is valid
checkServiceValid();
}
/**
* Method to check if the amount user input is valid , if not please ask
* user to select amount again until is valid
*/
public void checkAmountValid() {
while (this.amount <= 0) {
System.out.println("Invalid amount, please enter the amount again");
this.amount = console.nextDouble();
}
}
/**
* Method to ask the user to input amount and check if it valid
*/
public void inputAmount() {
switch(this.service){
case 1:
System.out.println("How much do you want to deposit today");
break;
case 2:
System.out.println("How much do you want to withdraw today?");
break;
case 3:
System.out.println("How much do you want to transfer today");
break;
}
this.amount = console.nextDouble();
// check if the amount is valid
checkAmountValid();
}
/**
* Method to update the balance based on the service user select
*
*/
public void updateBalance() {
switch (this.service) {
case 1: // deposit
this.balance += this.amount;
break;
case 2: // withraw
case 3:
this.balance -= this.amount;
break;
}
}
/**
* method to deposit an amount to the account
*
* @throws FileNotFoundException
*/
public void deposit() throws FileNotFoundException {
inputAmount();
this.balance = readBalanceFile(this.account);
updateBalance();
writeBalanceFile(this.account, this.balance);
writeHistoryFile(this.account, this.balance);
printSucces();
}
/**
* method to withdraw an amount from the account
*
* @throws FileNotFoundException
*/
public void withdraw() throws FileNotFoundException {
inputAmount();
this.balance = readBalanceFile(this.account);
updateBalance();
writeBalanceFile(this.account, this.balance);
writeHistoryFile(this.account, this.balance);
printSucces();
}
/**
* Method to print the current balance
*/
public void printBalance() {
System.out.printf("Your current balance is: $%.2f%n%n", this.balance);
}
public void displayBalance() throws FileNotFoundException {
balance = readBalanceFile(this.account);
printBalance();
}
/**
* method to provide the service
*
* @throws FileNotFoundException
*/
public void provideService() throws FileNotFoundException {
switch (service) {
case 1: // withdraw
deposit();
break;
case 2: // deposit
withdraw();
break;
case 3: // transfer
transfer();
case 4: // print balance
displayBalance();
break;
}
}
/**
* print the notice for success
*/
public void printSucces() {
switch (this.service) {
case 1:
System.out.println("Deposit successfuly...");
break;
case 2:
System.out.println("Withdraw successfuly...");
break;
case 3:
System.out.println("Transfer successfuly...");
break;
}
}
/**
* Ask the user to input the account he/she want to transfer
*
*/
public void inputDestinationAccount() {
System.out.println("Which account you want to transfer to? ");
this.destinationAccount = console.next();
}
public void transfer() throws FileNotFoundException {
double destinationBalance;
inputDestinationAccount();
inputAmount();
this.balance = readBalanceFile(this.account); // read my balance
destinationBalance = readBalanceFile(this.destinationAccount); // read
my detination balance
updateBalance(); // update my balance
writeBalanceFile(this.account, this.balance); // write my new balance
writeBalanceFile(this.destinationAccount, destinationBalance +
this.amount); // write the detination new balance
// setService(2);
writeHistoryFile(this.account, this.balance); // write my history
// setService(1);
writeHistoryFile(this.destinationAccount, destinationBalance +
this.amount); // write the
printSucces();
}
public void displaybalance(){
}
/**
*
*/
/**
* REad th ebalance from a txt file
*
* @param account the account u want to read
* @return the balance of that account
* @throws FileNotFoundException
*/
public double readBalanceFile(String account) throws FileNotFoundException {
double balance;
Scanner inFile = new Scanner(new FileReader(account + "_balance.txt"));
balance = inFile.nextDouble();
inFile.close();
return balance;
}
/**
* Method to write balance to the file
*
* @param account
* @param balance the current balance
* @throws FileNotFoundException
*/
public void writeBalanceFile(String account, double balance) throws
FileNotFoundException {
PrintWriter outFile = new PrintWriter(new FileOutputStream(new
File(this.account + "_balance.txt")));
outFile.print(balance);
outFile.close();
}
public void writeHistoryFile(String amount, double balance) throws
FileNotFoundException {
PrintWriter outFile = new PrintWriter(new FileOutputStream(new
File(this.account + "_history.txt"), true));
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("YYYY-MM-DD
HH:mm:ss");
//String DEPOSIT = "\u001B[32m";
//System.out.println((char)27 + "[33mYELLOW");
switch (service) {
case 1: // deposit
outFile.printf("%-40s%-20s%-10s%n", "DATE", "DEPOSIT", " BALANCE
");
outFile.printf("%-40s%-20.2f%-10.2f%n",
dtf.format(LocalDateTime.now()), this.amount, balance);
break;
case 2: // withdraw
outFile.printf("%-30s%-30s%-10s%n", " DATE ", " WITHDRAW ", "
BALANCE ");
outFile.printf("%-30s%-30.2f%10.2f%n",
dtf.format(LocalDateTime.now()), this.amount, balance);
break;
case 3:
outFile.printf("%-50s%-10.2f%10.2f%n",
dtf.format(LocalDateTime.now()), this.amount, balance);
break;
}
outFile.close();
}
//---------------- GET METHOD ----------------------------//
public int getService() {
return service;
}
public double getBalance() {
return balance;
}
public double getAmount() {
return amount;
}
public String getAcount() {
return account;
}
public String getPassword() {
return password;
}
//----------------- SET METHOD ----------------------------//
public void setService(int service) {
this.service = service;
}
public void setBalance(double balance) {
this.balance = balance;
}
public void setAmount(double amount) {
this.amount = amount;
}
public void setAcount() {
this.account = account;
}
public void setPassword() {
this.password = password;
}
//----------------------------------------------------------//
public String getDestinationAcaount() {
return destinationAccount;
}
public void setDestinationAcaount(String destinationAcaount) {
this.destinationAccount = destinationAcaount;
}
}
# 1 楼答案
问题在于writeBalanceFile方法。您使用了
this.account而不是传递给该方法的帐户。请将其更正为：另外，如果我可以提出一个建议：如果您将这个类拆分为3个类，那么理解和逻辑上遵循代码会容易得多。一个表示
Account，另一个处理Input，另一个用于读取和写入文件（FileHandler）