Java InputMismatchException？

Question

如果用户放入一个字符串而不是整数，我会尝试在我的代码上做一个异常。我的代码会将最大索引的位置交换为最小索引。你能试着和我一起纠正这个问题吗？

import java.util.Scanner;
import java.util.InputMismatchException;

public class ArraySwap 
{
    static int h;
    static Scanner data = new Scanner(System.in);
    static int[] list = new int[10];
    public static void main(String[] args)throws InputMismatchException
    {
        System.out.println("Please enter 10 numbers: ");
        for(h = 0; h < list.length; h++)
        {
        try
            {
                list[h] = data.nextInt();
            }
        catch(InputMismatchException h)
            {
                System.out.println("Please re-enter 10 numbers as an exception " 
                    + h.toString());
                continue;
            }
        }
        swap();
    }
    public static void printArray(int[] list)
    {
        int counter;
        for(counter = 0; counter < list.length; counter++)
            System.out.print(list[counter] + " ");
    }
    public static int smallestIndex(int[] list)
    {
        int length1 = list.length;
        int counter;
        int minIndex = 0;

        for (counter = 1; counter < length1; counter++)
            if (list[minIndex] > list[counter])
                minIndex = counter;
        return minIndex;
    }
    public static int largestIndex(int[] list)
    {
        int length2 = list.length;
        int counter;
        int maxIndex = 0;

        for (counter = 1; counter < length2; counter++)
            if (list[maxIndex] < list[counter])
                maxIndex = counter;
        return maxIndex;
    }
    public static void swap()
    {
        System.out.print("List of elements: ");
        printArray(list);
        System.out.println();

        int min_index = smallestIndex(list);
        int max_index = largestIndex(list);
        int min_num = list[min_index];

        System.out.println("Largest element in list is: " 
                + list[max_index]);

        System.out.println("Smallest element in list is: " 
                + list[min_index]);

        min_num = list[min_index];
        list[min_index] = list[max_index];
        list[max_index] = min_num;

        System.out.print("Revised list of elements: ");
        printArray(list);
        System.out.println();
    }
}

Answer 1

您已经在对整数输入进行异常处理：

   try
        {
            list[h] = data.nextInt();
        }
    catch(InputMismatchException h)
        {
            System.out.println("Please re-enter 10 numbers as an exception " 
                + h.toString());
            continue;
        }
    }

您的问题是，在catch块中，您将InputMismatchException对象命名为h。这也是循环计数变量。改变这一切。

catch(InputMismatchException ex)
    {
        System.out.println("Please re-enter 10 numbers as an exception " 
            + ex.toString());
        continue;
    }

另外，您的第二个问题是catch块中的print语句将自动作为下一次循环的Scanner输入。因此，一旦输入了错误字符串，程序就不允许输入更多的数字。您需要做的是首先使用data.next()来处理您的错误消息。

catch (InputMismatchException ex) {
                 System.out.print("Please re-enter 10 numbers as an exception "
                 + ex.toString());
                 data.next();

            }