code: public static JsonRtn shortUrl(License license, String url) {
          if (StringUtils.isEmpty(url)) {
              return JsonRtnUtil.buildFailureJsonRtn(JsonRtn.class, "missing url");
          }
  
          Map<String, String> paramMap = ImmutableMap.of("action", "long2short", "long_url", url);
          return HttpUtil.postBodyRequest(WechatRequest.SHORT_URL, license, paramMap, JsonRtn.class);
      }
docs: TODO-Shunli: now shortUrl always failed, user unauthorized, check later