如何克服线程“main”java.util.InputMismatchException中的异常

问：

程序：

import java.util.Scanner;

public class JavaExercise1 {
    static int sum, num1, num2;
    static Scanner scan = new Scanner(System.in);
    public static void add(){
        System.out.print("Enter first number to be added: ");
        num1 = scan.nextInt();
        System.out.print("Enter second number to be added: ");
        num2 = scan.nextInt();
        sum=num1+num2;
        System.out.println(num1+" + "+num2+" = "+sum);
    }
    static void sub(){
        System.out.print("Enter first number to be substracted: ");
        num1 = scan.nextInt();
        System.out.print("Enter second number to be substracted: ");
        num2 = scan.nextInt();
        sum=num1-num2;
        System.out.println(num1+" - "+num2+" = "+sum);
    }
    static void mul(){

            System.out.print("Enter first number to be multiplied: ");
            num1 = scan.nextInt();
            System.out.print("Enter second number to be multiplied: ");
            num2 = scan.nextInt();
            sum=num1*num2;
            System.out.println(num1+" x "+num2+" = "+sum);
    }
    static void div(){
        try{
            System.out.print("Enter first number to be divided: ");
            num1 = scan.nextInt();
            System.out.print("Entr second number to be divided: ");
            num2 = scan.nextInt();
            sum=num1/num2;
            System.out.println(num1+" / "+num2+" = "+sum);
        }catch(Exception e){
            System.out.println("\nException occured...");
            System.out.println(e);
        }
    }

    static void printInstructions(){
        System.out.println("1. Addition\n2. Substraction\n3. Multiplication\n4. Division\n5. Exit");
    }
    public static void main(String[] args) {
        int ch;
        do{
            System.out.println("\nEnter your choice: (Choose 0 to print instructions)");
            ch = scan.nextInt();
            switch(ch){
                case 0: printInstructions();
                        break;
                case 1: add();
                        break;
                case 2: sub();
                        break;
                case 3: mul();
                    break;
                case 4: div();
                    break;
                case 5: break;
                default:
                    System.out.println("Invalid choice....");
            }
        }while(ch!=5);

    }
}

当我输入一些更大的数字时，会抛出一个线程异常（线程“main”java.util.InputMismatchException中的异常）

输出：输入您的选择：
（选择 0 打印说明） 4 输入第一个要除数的数字：9999999999

发生异常... java.util.InputMismatchException：对于输入字符串：“9999999999”

输入您的选择：（选择 0 打印说明） 线程“main”java.util.InputMismatchException中的异常：对于输入字符串：“9999999999” 在 java.base/java.util.Scanner.nextInt（Scanner.java：2264） 在 java.base/java.util.Scanner.nextInt（Scanner.java：2212） 在 JavaExercise1.main（JavaExercise1.java：52）

进程完成，退出代码为 1