docs: private void updateOneConfItem(String keyName, DisconfCenterItem disconfCenterItem) throws Exception {
  
          if (disconfCenterItem == null) {
              throw new Exception("cannot find disconfCenterItem " + keyName);
          }
  
          String value = null;
  
          //
          // 开启disconf才需要远程下载, 否则就用默认值
          //
          if (DisClientConfig.getInstance().ENABLE_DISCONF) {
              //
              // 下载配置
              //
              try {
                  String url = disconfCenterItem.getRemoteServerUrl();
                  value = fetcherMgr.getValueFromServer(url);
                  if (value != null) {
                      LOGGER.debug("value: " + value);
                  }
              } catch (Exception e) {
                  LOGGER.error("cannot use remote configuration: " + keyName, e);
                  LOGGER.info("using local variable: " + keyName);
              }
              LOGGER.debug("download ok.");
          }
  
          //
          // 注入到仓库中
          //
          disconfStoreProcessor.inject2Store(keyName, new DisconfValue(value, null));
          LOGGER.debug("inject ok.");
  
          //
          // Watch
          //
          if (DisClientConfig.getInstance().ENABLE_DISCONF) {
              if (watchMgr != null) {
                  DisConfCommonModel disConfCommonModel = disconfStoreProcessor.getCommonModel(keyName);
                  watchMgr.watchPath(this, disConfCommonModel, keyName, DisConfigTypeEnum.ITEM, value);
                  LOGGER.debug("watch ok.");
              } else {
                  LOGGER.warn("cannot monitor {} because watch mgr is null", keyName);
              }
          }
      }