public void createFolder(String folderName) throws UpYunExcetion {
    try {
      StringBuffer url = new StringBuffer();
      for (String str : folderName.split("/")) {
        if (str == null || str.length() == 0) {
          continue;
        }
        url.append(UrlCodingUtil.encodeBase64(str.getBytes("utf-8")) + "/");
      }
      sign.setUri(url.toString());
    } catch (UnsupportedEncodingException e) {
      LogUtil.exception(logger, e);
    }
    sign.setContentLength(0);
    sign.setMethod(HttpMethodEnum.POST.name());
    String url = autoUrl + sign.getUri();
    Map<String, String> headers = sign.getHeaders();
    headers.put("folder", "true");
    headers.put("mkdir", "true");

    HttpResponse httpResponse = HttpClientUtils.postByHttp(url, headers);
    if (httpResponse.getStatusLine().getStatusCode() != 200) {
      throw new UpYunExcetion(
          httpResponse.getStatusLine().getStatusCode(),
          httpResponse.getStatusLine().getReasonPhrase());
    }
  }