public static InputStream downFile(String groupName, String remoteFileName) { try { StorageClient storageClient = getTrackerClient(); byte[] fileByte = storageClient.download_file(groupName, remoteFileName); InputStream ins = new ByteArrayInputStream(fileByte); return ins; } catch (IOException e) { logger.error("IO Exception: Get File from Fast DFS failed", e); } catch (Exception e) { logger.error("Non IO Exception: Get File from Fast DFS failed", e); } return null; }這是我工具類里面下載功能，請問在控制臺這邊怎么實現下載？