while循環內的Java try-catch語句

Question

我有這種方法，它工作正常。 我需要放置一條try / catch語句，以便在用戶輸入字母時該方法可以繼續。 我不知道該聲明放在何處，似乎到處我都說錯了。 有人可以告訴我該聲明放在何處嗎？

public void myMethod() {

    Scanner in = new Scanner(System.in);
    int array[] = new int[21];
    int number;

    boolean end = false;

    while (!end) {

        System.out.println("Please give an number between 0-20: ");
        number = in.nextInt();

        for (int i = 1; i < array.length; i++) {

            if (i == number) {

                System.out.println(array[number]);
                end = true;
            }
        }
        if (!end) {
            System.out.println("I cant find number " + number
                    + " in the array, please try again ");
        }

    }

 }

Answer 1

    System.out.println("Please give an number between 0-20: ");
    try{
        number = in.nextInt();
    }catch(Exception e){
        number = 1; //Put random number of default number here
    }

Answer 2

public static void main(String[] args) {

    Test test = new Test();
    Scanner in = new Scanner(System.in);
    int array[] = new int[21];  
    int number;
    System.out.println("Please give an number between 0-20: ");
    do{
        try{
            number = Integer.parseInt(in.next());
        }
        catch(Exception e){
            System.out.println("Please give an number between 0-20: ");
            number = -1;
        }
    }
    while(!(number <= 20 && number >=0 ));
    System.out.println(array[number]);
}

Answer 3

我無法解釋您的for循環，您只需要檢查0到20之間的值，並且當您調用try catch時，必須在異常發生后跳過循環

public static void myMethod() {

    Scanner in = new Scanner(System.in);
    int array[] = new int[21];
    int number=0;

    boolean end = false;

    while (!end) {


        System.out.println("Please give an number between 0-20: ");
        //check symbol
        try{
            number = Integer.valueOf(in.next());
        }catch(Exception e)
        {
            System.out.println("It's not a number! ");
            continue; //skip loop
        }

        if((number>=0)&&(number<=20))
        {
              System.out.println(array[number]);
              end=true;
        }
        else
             System.out.println("I cant find number " + number
                        + " in the array, please try again ");

        /* why do you use loop here???
         * u need to check if number between 0-20
        for (int i = 1; i < array.length; i++) {

            if (i == number) {

                System.out.println(array[number]);
                end = true;
            }
        }*/


    }

 }