Gestion NoSuchElementException StringTokenizer

Bonjour tout le monde,

J'aimerais gérer le NoSuchElementException du StringTokenizer lorsque le champs username ou password n'est pas indiqué mais je n'arrive pas à le gérer.

final String encodedUserPassword = authCredentials.replaceFirst("Basic"
				+ " ", "");
		String usernameAndPassword = null;
		try {
			byte[] decodedBytes = Base64.decode(
					encodedUserPassword);
			usernameAndPassword = new String(decodedBytes, "UTF-8");
		} catch (IOException e) {
			e.printStackTrace();
		}
		final StringTokenizer tokenizer = new StringTokenizer(
				usernameAndPassword, ":");
		
		System.out.println(usernameAndPassword);
		
		while(tokenizer.hasMoreTokens()){
				
			
			
				String tmp1 = tokenizer.nextToken();
			
				if (tokenizer.nextToken() == null){
					System.out.println("pas d'username");
					username = "";
				}
				else{
					username = tmp1;
				}
				
				
				String tmp2 = tokenizer.nextToken();
				
				if (tokenizer.nextToken() == null){
					System.out.println("pas de password");
					password = "";
				}
				else{
					password = tmp2;
				}
			
		}

Merci à vous.