code: ZoneInfo queryByToken(String token) {
          try {
              // http://developer.qiniu.com/article/developer/security/upload-token.html
              // http://developer.qiniu.com/article/developer/security/put-policy.html
              String[] strings = token.split(":");
              String ak = strings[0];
              String policy = new String(UrlSafeBase64.decode(strings[2]), Constants.UTF_8);
              JSONObject obj = new JSONObject(policy);
              String scope = obj.getString("scope");
              String bkt = scope.split(":")[0];
              return zoneInfo(ak, bkt);
          } catch (Exception e) {
              e.printStackTrace();
          }
          return null;
      }
docs: only for test public