docs: public static FetcherMgr getFetcherMgr() throws Exception {
  
          if (!ConfigMgr.isInit()) {
              throw new Exception("ConfigMgr should be init before FetcherFactory.getFetcherMgr");
          }
  
          // 获取一个默认的抓取器
          RestfulMgr restfulMgr = RestfulFactory.getRestfulMgrNomal();
  
          FetcherMgr fetcherMgr =
                  new FetcherMgrImpl(restfulMgr, DisClientConfig.getInstance().CONF_SERVER_URL_RETRY_TIMES,
                          DisClientConfig.getInstance().confServerUrlRetrySleepSeconds,
                          DisClientConfig.getInstance().enableLocalDownloadDirInClassPath,
                          DisClientConfig.getInstance().userDefineDownloadDir,
                          DisClientSysConfig.getInstance().LOCAL_DOWNLOAD_DIR,
                          DisClientConfig.getInstance().getHostList());
  
          return fetcherMgr;
      }