httpcommonlib/src/main/java/com/streamsets/pipeline/lib/http/HttpReceiverServlet.java
@VisibleForTesting
  protected static Map<String, String[]> getQueryParameters(HttpServletRequest request) {
    Map<String, String[]> queryParameters = new HashMap<>();
    String queryString = request.getQueryString();

    if (StringUtils.isEmpty(queryString)) {
      return queryParameters;
    }

    String[] parameters = queryString.split("&");

    for (String parameter : parameters) {
      String[] keyValuePair = parameter.split("=");
      String[] values = queryParameters.get(keyValuePair[0]);
      values = ArrayUtils.add(values, keyValuePair.length == 1 ? "" : keyValuePair[1]); //length is one if no value is available.
      queryParameters.put(keyValuePair[0], values);
    }
    return queryParameters;
  }
@VisibleForTesting
  protected static Map<String, String[]> getQueryParameters(HttpServletRequest request) {
    Map<String, String[]> queryParameters = new HashMap<>();
    String queryString = request.getQueryString();

    if (StringUtils.isEmpty(queryString)) {
      return queryParameters;
    }

    String[] parameters = queryString.split("&");

    for (String parameter : parameters) {
      String[] keyValuePair = parameter.split("=");
      String[] values = queryParameters.get(keyValuePair[0]);
      values = ArrayUtils.add(values, keyValuePair.length == 1 ? "" : keyValuePair[1]); //length is one if no value is available.
      queryParameters.put(keyValuePair[0], values);
    }
    return queryParameters;
  }
From https://stackoverflow.com/a/31928740/33905