检查用户输入是否为Int而没有异常？

Question

我试图创建一个简单的程序，从用户输入中提取两个数字，并将它们相加在一起。为了正确使用它，我已经把它放下来了，但是如果用户输入其他东西，比如字符串，我会试图阻止崩溃。我如何检查输入而没有异常，因为我听说它们是糟糕的做法？

理想情况下，我希望它只是重复最初的问题，要求输入一个数字。我想这会在一个循环中？

编辑：新代码

import java.util.Scanner;

public class App {

    public static void main(String[] args) {

       Scanner scan;

    scan = new Scanner(System.in);
    int firstNumber = Integer.MIN_VALUE;
    int secondNumber = Integer.MIN_VALUE;

    do {
        System.out.print("Enter the first number to be added: ");
        if (scan.hasNextInt()) {
            firstNumber = scan.nextInt();
        }
    }
    while(firstNumber != Integer.MIN_VALUE);


    do {
        System.out.print("Enter the second number to be added: ");
        if (scan.hasNextInt()) {
            secondNumber = scan.nextInt();
        }
    }
    while(secondNumber != Integer.MIN_VALUE);

    if ((firstNumber != Integer.MIN_VALUE) && (secondNumber != Integer.MIN_VALUE)) {
        int sum = secondNumber + firstNumber;
        System.out.println("That equals: " + sum);
    }
    scan.close();
    }
}

旧代码

import java.util.Scanner;

public class calculate {
    private static Scanner scan;

    public static void main(String[] args) {

        scan = new Scanner(System.in);

        System.out.print("Enter the first number to be added: ");
        int firstNumber = scan.nextInt();

        System.out.println("Enter the second number to be added: ");
        int secondNumber = scan.nextInt();

        int sum = secondNumber + firstNumber;

        System.out.println("That equals: "+ sum);
    }
}

Answer 1

您可以简单地使用：

if(scan.hasNextInt()) {//<-- get in if its a number
  int firstNumber = scan.nextInt();
}