code: private static boolean checkDownloadPath() {
          if (Checker.isNotEmpty(storageFolder)) {
              File file = new File(storageFolder);
              if (!file.exists() && file.mkdirs()) {
                  logger.info("mkdir '" + storageFolder + "' success");
              }
              return true;
          }
          return false;
      }
docs: 检测下载目录是否存在，不存在则创建
  
  @return {@link Boolean}