java - 如果输入整数以外的任何内容，则要求用户仅输入整数

Question

我目前正在使用 Java 编程来创建“Nim”游戏。但是，我完全不知道如何修改我的程序以使用户仅输入整数，如果他们输入其他任何内容，请要求他们输入整数。

import java.util.Scanner;

public class Nim 
{
    public static void main(String[] args) 
    {
        Scanner scanner = new Scanner(System.in);

        int noEntered;

        int firstPile = 3;
        int secondPile = 4;
        int thirdPile = 5;

        int next = 1;

        int choose;

        do 
        {
            if (next % 2 == 1) 
            {
                System.out.print("Player 1 - choose bag: ");
                choose = scanner.nextInt();

                if (choose == 1) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    firstPile = firstPile - noEntered;
                    System.out.println("Bag Status: " + + firstPile + ", " + secondPile + ", " 
                    + thirdPile);
                } 
                else if (choose == 2) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    secondPile = secondPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } 
                else if (choose == 3) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    thirdPile = thirdPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }        
            }
            else
            {
                System.out.print("Player 2 - choose bag: ");
                choose = scanner.nextInt();
                if (choose == 1) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    firstPile = firstPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }
                else if (choose == 2)
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    secondPile = secondPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } 
                else if (choose == 1) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    thirdPile = thirdPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }              
            }
            next++;
        } 
        while (firstPile != 0 && secondPile != 0 && thirdPile != 0);

        if (next % 2 == 1) 
        {
            System.out.println("Game Over - Player 1 wins");
        } 
        else if (next % 2 == 0)
        {
            System.out.println("Game Over - Player 2 wins");
        }
    }
}

有什么帮助吗？谢谢。

Answer 1

像这样使用try和catch()，

try{
        System.out.print("Player 1 - choose bag: ");
        choose = scanner.nextInt();
}catch(InputMismatchException exception)
{
  System.out.println("This is not an integer");
}

更新:

import java.util.Scanner;

public class Nim 
{
  public static void main(String[] args) 
  {
   try{
    Scanner scanner = new Scanner(System.in);
    int noEntered;
    int firstPile = 3;
    int secondPile = 4;
    int thirdPile = 5;

    int next = 1;

    int choose;

    do 
    {
        if (next % 2 == 1) 
        {
            System.out.print("Player 1 - choose bag: ");
            choose = scanner.nextInt();

            if (choose == 1) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                firstPile = firstPile - noEntered;
                System.out.println("Bag Status: " + + firstPile + ", " + secondPile + ", " 
                + thirdPile);
            } 
            else if (choose == 2) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                secondPile = secondPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            } 
            else if (choose == 3) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                thirdPile = thirdPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            }        
        }
        else
        {
            System.out.print("Player 2 - choose bag: ");
            choose = scanner.nextInt();
            if (choose == 1) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                firstPile = firstPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            }
            else if (choose == 2)
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                secondPile = secondPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            } 
            else if (choose == 1) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                thirdPile = thirdPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            }              
        }
        next++;
    } 
    while (firstPile != 0 && secondPile != 0 && thirdPile != 0);

    if (next % 2 == 1) 
    {
        System.out.println("Game Over - Player 1 wins");
    } 
    else if (next % 2 == 0)
    {
        System.out.println("Game Over - Player 2 wins");
    }
   }catch(InputMismatchException exception){
        System.out.println("Given input is not a number");
      }
   }
  }