docs: private Object convertStrToObjTree(String s) {
          Object contentObj = null;
          if (s != null) {
              s = s.trim();
              try {
                  if (s.startsWith("{")) {
                      contentObj = Config.getInstance().getMapper().readValue(s, new TypeReference<HashMap<String, Object>>() {
                      });
                  } else if (s.startsWith("[")) {
                      contentObj = Config.getInstance().getMapper().readValue(s, new TypeReference<List<Object>>() {
                      });
                  } else {
                      logger.error("cannot deserialize json str: {}", s);
                      return null;
                  }
              } catch (IOException e) {
                  logger.error(e.getMessage());
              }
          }
          return contentObj;
      }