How to find sum of digits in a number

import java.util.Scanner;
public class SumOfDigitsInNumber {
	public static void main(String[] args) {
		Scanner inpStr = new Scanner(System.in);
		System.out.println("Enter a number");
		String inpLine = inpStr.nextLine();
		/*
		 * Basic validations - Checking if the input number is empty or if it contains
		 * more than one number, or if it's purely numeric (no alphabets or symbols).
		 */
		if (inpLine.isEmpty())
			System.out.println("Given number is empty");
		else if (inpLine.split("\\s").length > 1)
			System.out.println("Input can only contain one number");
		else if (!isValidInput(inpLine))
			System.out.println("The input should be a number");
		else {
			inpStr.close();
			System.out.printf("The sum of all the digits in the number is %d", sumOfDigits(inpLine)).println();
		}
	}
	private static boolean isValidInput(String s) {
		/*
		 * This method uses regular expressions to check if the input number is valid by
		 * checking if it only contains digits and returning true if it does.
		 */
		if (s.matches("[0-9]*$") && s.matches("[^a-zA-Z]*$"))
			return true;
		else
			return false;
	}
	private static int sumOfDigits(String s) {
		/*
		 * This method runs through the input string and adds up every single digit to a
		 * variable which is returned at the end
		 */
		int digitAdder = 0;
		try {
			for (int i = 0; i < s.length(); i++) {
				digitAdder += ((int) s.charAt(i) - 48); // ASCII value
			}
		} catch (Exception e) {
			System.out.printf("Exception is %s", e).println();
		}
		return digitAdder;
	}
}