Verificar IBAN

[aux_code language=»javascript» theme=»tomorrow» title=»Verificar IBAN» extra_classes=»»]

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String iban = "";
        do {
            try {
                System.out.println("Calcular IBAN de 24 dígitos:");
                iban = br.readLine().toUpperCase();
                if (iban.equals("FIN")) {
                    System.out.println("Fin del programa.");
                } else {
                    if (verificar(iban)) {
                        System.out.println("Ok");
                    } else {
                        System.out.println("Error");
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } while (!iban.equals("FIN"));

    }

    private static boolean verificar(String iban) {
        //trim no acorta los espacios entre palabras
        iban = iban.replace(" ", "");
        // si tiene los 2 iniciales en letras;
        if (isNotNumeric(iban.charAt(0)) && isNotNumeric(iban.charAt(1)) && iban.length() > 4) {
            iban = iban.replace(iban.substring(0, 4), "") + iban.substring(0, 4);
            for (int x = 0; x < iban.length(); x++) {
                char l = iban.charAt(x);
                if (isNotNumeric(l)) {
                    iban = iban.replace(String.valueOf(l), String.valueOf(calcLetra(l)));
                }
            }
            return comprobar(iban).equalsIgnoreCase("1");
        } else {
            return false;
        }
    }

    private static String comprobar(String iban) {
        if (iban.length() >= 9) {
            int calcular = Integer.parseInt(iban.substring(0, 9));
            int resto = calcular % 97;
            String restoIban = resto + iban.substring(9);
            return comprobar(restoIban);
        } else {
            int sobra = Integer.parseInt(iban);
            return String.valueOf((sobra % 97));
        }
    }

    private static int calcLetra(char v) {
        return v - 55;
    }

    private static boolean isNotNumeric(char dato) {
        try {
            Integer.parseInt(String.valueOf(dato));
            return false;
        } catch (NumberFormatException e) {
            return true;
        }
    }

}

[/aux_code]