code: private void fillParams(final Map<String, String[]> params, final String queryString, Charset charset) {
          if (StringUtils.hasText(queryString)) {
              final StringTokenizer tokenizer = new StringTokenizer(queryString, "&");
              while (tokenizer.hasMoreTokens()) {
                  final String[] nameValuePair = tokenizer.nextToken().split("=");
  
                  try {
                      params.put(URLDecoder.decode(nameValuePair[0], charset.name()),
                              new String[] { URLDecoder.decode(nameValuePair[1], charset.name()) });
                  } catch (final UnsupportedEncodingException e) {
                      throw new CitrusRuntimeException(String.format(
                              "Failed to decode query param value '%s=%s'",
                              nameValuePair[0],
                              nameValuePair[1]), e);
                  }
              }
          }
      }
docs: Adds parameter name value paris extracted from given query string.
  @param params The parameter map to alter
  @param queryString The query string to extract the values from
  @param charset