java - 读写txt文件

Question

我正在编写一段代码，读取文件 Banking.txt 并询问用户 ID 和密码，然后提示用户进行提款、存款或查询余额。余额将写入 Records.txt。程序在用户输入密码后终止，我不知道如何让它继续。请帮忙

public static void main(String[] args) throws FileNotFoundException {
    File fil1 = new File("Banking.txt");
    File fil2 = new File("Records.txt");
    Scanner sc1 = new Scanner(fil1);
    Scanner s1 = new Scanner(fil2);
    String fname;
    String mname;
    String lname;
    String uid = null;
    int pin = 0;
    double balance = 0;
    java.io.PrintWriter output = new java.io.PrintWriter(fil2); 
    while (sc1.hasNext()) {
        fname = sc1.next();
        mname = sc1.next();
        lname = sc1.next();
        uid = sc1.next();
        pin = sc1.nextInt();
        balance = sc1.nextDouble();
        BankRecord person = new BankRecord(fname,mname,lname,uid,pin,balance);
        System.out.print(pin);
    }

Scanner input = new Scanner(System.in); 
System.out.print("Please enter a user ID: ");
String entereduid = input.nextLine();
if(entereduid.equals(uid)){
System.out.print("Please enter a Pin #: "); 
String enteredpin = input.nextLine();
if(enteredpin.equals(pin)){
Scanner input2 = new Scanner(System.in);
System.out.print("press 1 to check balance, 2 for a deposit, or 3 for a withdrawal: "); 
int ans = input.nextInt();
if(ans == 1){
System.out.print(balance);
output.println("The balance is now "+balance+"$.");
}
else if(ans == 2){
    System.out.print("Your current balance is: " + balance+". Please enter an amount to deposit: ");
    double dep = input.nextDouble();
    balance = balance + dep;
    System.out.print("You deposited "+dep+"$. Your new balance is: " + balance+"$.");
    output.println("The balance is now "+balance+"$.");
}
else if(ans == 3){
    System.out.print("Yor current balance is: "+balance+". Please enter an amount to withdrawl: ");
    double wit = input.nextDouble();
    balance = balance - wit;
    System.out.print("You withdrew "+wit+"$. Your new balance is: "+balance+"$.");
    output.println("The balance is now "+balance+"$.");

}}}}}

Answer 1

您正在以字符串形式从输入中读取 pin，但您以整数形式从文件中读取它；所以 Integer pin != String pin。您的 pin 永远不会被识别为正确的，因此您的程序会跳到最后。

尝试 new Scanner(System.in).nextInt() 将输入读取为整数。

所以我会改变这一行:

String enteredpin = input.nextLine();

为此:

Integer enteredpin = input.nextInt();