java - 扫描仪 Try Catch 语句导致 java.util.InputMismatchException

Question

为什么我的代码出现错误？如果用户输入了错误的号码，代码不应该让我输入新的有效号码吗？似乎它不允许我将最喜欢的值更改为新值。我怎样才能解决这个问题？

package RobB;

import java.util.Scanner;

public class FavoriteNum {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int[] num = new int[10];
        int favorite = 0;

        System.out.print("Enter your favorite number: ");
        try {
            favorite = scan.nextInt();
        }
        catch (Exception e) {
            System.out.println("Enter an integer!");
            System.out.print("Enter your favorite number: ");

            favorite = scan.nextInt();
        }

        for (int i = 0; i < 10; i++) {
            System.out.print("Enter a random number (" + Math.abs(((i + 1) - 10)) + " to go): ");
            num[i] = scan.nextInt();
        }
    }
}

控制台输出:

Enter your favorite number: 11.1

Enter an integer!

Exception in thread "main" Enter your favorite number: java.util.InputMismatchException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at RobB.FavoriteNum.main(FavoriteNum.java:21)

Answer 1

这是一个 while 循环的替代方案:

boolean validInput = false;
while (!validInput) {
   try {
        System.out.print("Enter your favourite number: ");
        favorite = scan.nextInt();
        validInput = true;
    }
    catch (Exception e) {
        System.out.println("Enter an integer!");
    }
}