使用 InputMismatchException try/catch 块

Question

我想捕获任何不是 Int 的输入并提示输入有效输入 3 次。 3 次后，程序将继续并要求另一个评级。我似乎无法重复 try/catch 块，甚至无法捕获 InputMismatchException。有什么建议吗？

do {
    //prompt for rating
        try {
        System.out.println("Enter a rating between 0-4 for the Movie of the Week (Enter -1 to stop/exit): ");
        //capture
            rating = response.nextInt();
        } catch (InputMismatchException err) {
            System.out.println("Invalid input. Please enter a rating 0-4 or enter -1 to exit: ");
            rating = response.nextInt();
        } //end catch
    } while (rating >= 0);

Answer 1

您可以循环执行：

int count = 0;
do {
    //prompt for rating
        try {
        System.out.println("Enter a rating between 0-4 for the Movie of the Week (Enter -1 to stop/exit): ");
        //capture
            rating = response.nextInt();
        } catch (InputMismatchException err) {
            System.out.println("Invalid input. Please enter a rating 0-4 or enter -1 to exit: ");
            count++;
        } //end catch
    } while (rating >= 0 && count < 3);

或者使用嵌套的 try/catch：

do {
    //prompt for rating
        try {
        System.out.println("Enter a rating between 0-4 for the Movie of the Week (Enter -1 to stop/exit): ");
        //capture
            rating = response.nextInt();
        } catch (InputMismatchException err) {
            System.out.println("Invalid input. Please enter a rating 0-4 or enter -1 to exit: ");
             try {
        System.out.println("Enter a rating between 0-4 for the Movie of the Week (Enter -1 to stop/exit): ");
        //capture
            rating = response.nextInt();
        } catch (InputMismatchException err) {
            System.out.println("Invalid input. Please enter a rating 0-4 or enter -1 to exit: ");
            rating = response.nextInt();
        } //end catch
        } //end catch
    } while (rating >= 0);

我个人更喜欢第一种方法。

我试过这段代码，它运行时没有任何异常：

公共类主{

public static void main(String[] args) throws IOException {
    int count = 0;
    int rating = 0;
    do {
        Scanner response = new Scanner(System.in);
        //prompt for rating
            try {
            System.out.println("Enter a rating between 0-4 for the Movie of the Week (Enter -1 to stop/exit): ");
            //capture
                rating = response.nextInt();

            } catch (InputMismatchException err) {
                System.out.println("Invalid input. Please enter a rating 0-4 or enter -1 to exit: ");
            } finally {
                count++;
                System.out.println("Rating-->" + rating);
            }
      } while (rating >= 0 && count < 3);

}

}