org.apache.commons.codec.DecoderException: Odd number of characters

Question

Sending hex string in url parameter and trying to convert it in to string at server side. Converting user input string by using following javascript encoding code

function encode(string) {
     var number = "";
        var length = string.trim().length;
        string = string.trim();
        for (var i = 0; i < length; i++){
            number += string.charCodeAt(i).toString(16);
            }
        return number;
}

Now I'm trying to parse hex string 419 for russian character Й in java code as follows

  byte[] bytes = "".getBytes();

   try {
        bytes = Hex.decodeHex(hex.toCharArray());
        sb.append(new String(bytes,"UTF-8"));
    } catch (DecoderException e) {      
      e.printStackTrace(); // Here it gives error 'Odd number of characters'
    }catch (UnsupportedEncodingException e) {           
      e.printStackTrace();
    }

but it gives following error

"org.apache.commons.codec.DecoderException: Odd number of characters." 

How it can be resolved. As there are many russian character have hex code 3 digit and due to this it is not able to convert it to .toCharArray()

Answer 1

Use Base64 instead

val aes = KeyGenerator.getInstance("AES")
aes.init(128)
val secretKeySpec = aes.generateKey()
val base64 = Base64.encodeToString(secretKeySpec.encoded, 0)
val bytes = Base64.decode(base64, 0)
SecretKeySpec(bytes, 0, bytes.size, "AES") == secretKeySpec