爲什麼這種獲取用戶輸入的方法不起作用？

我有我正在使用的以下代碼讓用戶輸入一個整數，檢查以確保輸入有效，如果沒有，請再次輸入。當代碼運行時，一切正常，直到給出一些無效的輸入爲止，此時代碼會循環而不會暫停，直到發生堆棧溢出時再次請求輸入，我不知道爲什麼。代碼：爲什麼這種獲取用戶輸入的方法不起作用？

//Create the scanner object 
private static Scanner in = new Scanner(System.in); 

//Function to get input in integer form, complete with exception handling 
//A value of -1 means the user is done inputing 
public static int getInt() 
{ 
    int num; 

    //Begin try block 
    try 
    { 
     //Get the user to input an integer 
     num = in.nextInt(); 

     //Make sure the integer is positive. Throw an exception otherwise 
     if (num < -1) 
      throw new InputMismatchException(); 
    } 

    //If an exception occurred during the inputting process, recursively call this function 
    catch (InputMismatchException e) 
    { 
     System.out.println("Error: Input must be a positive integer, or -1."); 
     System.out.print("Enter a score: "); 
     num = getInt(); 
    } 

    //Return the inputed number 
    return num; 
}

來源

2010-11-15 Lewis