Handle InputMismatchException exception but doesn't catch it Java-CodePudding

For some unknown reason, when the user input is a string or special characters it doesn't catch my exception (the scanner accepts only integers and from 1 to 3). The code is the below:

package mainpackage;
import java.util.InputMismatchException;
import java.util.Scanner;

public class CreateUsers {
    
    public static void main(String[] args) {
        
        Scanner chooseNumber = new Scanner(System.in);
        int number;
        
        System.out.println("Welcome to UniStudents Application!\n"
                  "Please select how to Log in: \n"
                  "1. Log in as a Student \n"
                  "2. Log in as a Professor \n"
                  "3. Log in as a Secretary \n"
                  "To choose an action, please write the number of the action: ");  
        number = chooseNumber.nextInt();
        
        while(true) {
            if(number > 3 || number < 1) {
                System.out.println("The number of the action does not exist.\n"
                         "Please try again: ");
                chooseNumber.nextInt();
            }
            else {
                System.out.println("ok");
                chooseNumber.close();
                break;
            }   
        }
        try{
            chooseNumber.nextInt();
        }
        catch(InputMismatchException e) {
             
            System.out.println("Please write the number of the action you want to choose \n"
                      "Please select how to Log in: \n"
                      "1. Log in as a Student \n"
                      "2. Log in as a Professor\n"
                      "3. Log in as a Secretary\n");
        }

The result of the code is that:

1. Log in as a Student 
2. Log in as a Professor 
3. Log in as a Secretary 
To choose an action, please write the number of the action: 
$^&*
Exception in thread "main" java.util.InputMismatchException
    at java.base/java.util.Scanner.throwFor(Scanner.java:939)
    at java.base/java.util.Scanner.next(Scanner.java:1594)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2258)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2212)
    at JavaBasics/mainpackage.CreateUsers.main(CreateUsers.java:18)

I can't figure it out

CodePudding user response：

The first call to number = chooseNumber.nextInt(); is not in the try block, so the exception isn't caught. Move the beginning of the try block above it and you should be fine.

CodePudding user response：

Because this exception is thrown at line 18, which is number = chooseNumber.nextInt(); above while (true), and it is not covered by the try-catch block, try:

package mainpackage;
import java.util.InputMismatchException;
import java.util.Scanner;

public class CreateUsers {
    
    public static void main(String[] args) {
        
        Scanner chooseNumber = new Scanner(System.in);
        int number;
        
        System.out.println("Welcome to UniStudents Application!\n"
                  "Please select how to Log in: \n"
                  "1. Log in as a Student \n"
                  "2. Log in as a Professor \n"
                  "3. Log in as a Secretary \n"
                  "To choose an action, please write the number of the action: ");  
        try {
            number = chooseNumber.nextInt();
        
            while(true) {
                if(number > 3 || number < 1) {
                    System.out.println("The number of the action does not exist.\n"
                             "Please try again: ");
                    chooseNumber.nextInt();
                }
                else {
                    System.out.println("ok");
                    chooseNumber.close();
                    break;
                }   
            }
            chooseNumber.nextInt();
        } catch (InputMismatchException e) {
             
            System.out.println("Please write the number of the action you want to choose \n"
                      "Please select how to Log in: \n"
                      "1. Log in as a Student \n"
                      "2. Log in as a Professor\n"
                      "3. Log in as a Secretary\n");
        }