java - 文件不存在？线程 "main"java.io.FileNotFoundException : - Java 中出现异常

Question

我正在开发一个类(class)项目，我正在尝试创建一个读取文件并填充数组的方法。在该方法内部，我还使用了从我创建的类中调用的另一个方法。我提示用户输入要读取的文件，无论我做什么，我都会收到文件不存在的错误。

这是我正在使用的开始代码:

 public static void main(String[] args) throws Exception {
    Scanner input = new Scanner(System.in);
    System.out.print("Enter the file to read from:");
    String readFile = input.nextLine();
    System.out.print("Enter the number of accounts in the file: ");
    int size = input.nextInt();
    Account[] Accounts = readFile(readFile, size);
    Account[] invalidAccounts = new Account[34];
    for (int i = 0; i < Accounts.length; i++) {
        String password = Accounts[i].getPassword();
        if (isValidPassword(password) == false) {
            invalidAccounts[i] = Accounts[i];
        }
    }
    createDistributionList(invalidAccounts);
}
public static Account[] readFile(String readFile, int size) throws Exception {
    Account[] Accounts = new Account[size];
    File myFile = new File(readFile);
    Scanner fileInput = new Scanner(myFile);
    for (int i = 0; i < Accounts.length; i++) {
            int stuID = fileInput.nextInt();
            String name = fileInput.next();
            String username = fileInput.next();
            String password = fileInput.next();
            Accounts[i] = new Account(stuID, name, username, password);
    }
    return Accounts;
}

这是我使用引号时得到的跟踪:

Enter the file to read from:"studentdata.txt"
Enter the number of accounts in the file: 34
Exception in thread "main" java.io.FileNotFoundException: "studentdata.txt" (The filename, directory name, or volume label syntax is incorrect)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:146)
    at java.util.Scanner.<init>(Scanner.java:656)
    at accountdriver.AccountDriver.readFile(AccountDriver.java:38)
    at accountdriver.AccountDriver.main(AccountDriver.java:25)
Java Result: 1

这是不带引号的跟踪:

Enter the file to read from:studentdata.txt
Enter the number of accounts in the file: 34
Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:909)
    at java.util.Scanner.next(Scanner.java:1530)
    at java.util.Scanner.nextInt(Scanner.java:2160)
    at java.util.Scanner.nextInt(Scanner.java:2119)
    at accountdriver.AccountDriver.readFile(AccountDriver.java:40)
    at accountdriver.AccountDriver.main(AccountDriver.java:25)
Java Result: 1
BUILD SUCCESSFUL (total time: 7 seconds)

这是正常工作的代码:

public static void main(String[] args) throws Exception {
    Scanner input = new Scanner(System.in);
    System.out.print("Enter the file to read from:");
    String readFile = input.nextLine();
    System.out.print("Enter the number of accounts in the file: ");
    int size = input.nextInt();
    Account[] Accounts = readFile(readFile, size);
    Account[] invalidAccounts = new Account[34];
    for (int i = 0; i < Accounts.length; i++) {
        String password = Accounts[i].getPassword();
        if (isValidPassword(password) == false) {
            invalidAccounts[i] = Accounts[i];
        }
    }
    createDistributionList(invalidAccounts);
}
public static Account[] readFile(String readFile, int size) throws Exception {
    Account[] Accounts = new Account[size];
    File myFile = new File(readFile);
    Scanner fileInput = new Scanner(myFile);
    for (int i = 0; i < Accounts.length; i++) {
            int stuID = fileInput.nextInt();
            String name = fileInput.nextLine();
            String username = fileInput.nextLine();
            String password = fileInput.nextLine();
            Accounts[i] = new Account(stuID, name, username, password);
    }
    return Accounts;
}

当我尝试读取字符串时，我只需要在每个 fileInput.next 的末尾添加 Line 即可。

Answer 1

堆栈跟踪包含

"The filename, directory name, or volume label syntax is incorrect"

表明名称中存在特殊字符。看起来您在名称两边加上了 "引号。

Enter the file to read from:"studentdata.txt"

如果文件名是源代码中的 Java 字符串，则需要使用引号，但通过控制台输入文本时，不需要使用引号。