code: public URLNormalizer encodeSpaces() {
          String path = StringUtils.substringBefore(url, "?");
          path = StringUtils.replace(path, " ", "%20", -1);
          String qs = StringUtils.substringAfter(url, "?");
          if (StringUtils.isNotBlank(qs)) {
              qs = StringUtils.replace(qs, " ", "+", -1);
              url = path + "?" + qs;
          } else {
              url = path;
          }
          return this;
      }
docs: <p>
  Encodes space characters into plus signs (+) if they are part of the
  query string. Spaces part of the URL path are percent-encoded to %20.
  </p>
  <p>
  To encode all non-ASCII characters (including spaces), use
  {@link #encodeNonURICharacters()} instead.
  </p>
  <code>http://www.example.com/a b c &rarr;
  http://www.example.com/a+b+c</code>
  @return this instance
  @since 1.8.0