.net实现FTP传输文件的详细教程

   优点：不依靠其他任何依赖，可以实现自己需要的各种自定需求的操作
   缺点：手动实现起来麻烦，操作繁琐，自己实现需要考虑各种异常情况等等

   优点：实现起来简单，使用起来方便，功能丰富
   缺点：必须要添加项目依赖Nuget包FluentFTP

   /// <summary>
   /// ftp传输
   /// </summary>
   /// <param name="ftpSavePath">ftp保存地址 例：ftp://172.18.18.53/172.18.18.101/</param>
   /// <param name="ftpFileName">ftp保存文件名称 例：htrs_1.mp4</param>
   /// <param name="localFilePath">本地文件路径 例：C:\\files\\htrs_1.mp4</param>
   /// <param name="userName">ftp用户名</param>
   /// <param name="password">ftp密码</param>
   public static bool FTPUploadFile(string ftpSavePath, string ftpFileName, string localFilePath, string userName, string password)
   {
       if (!File.Exists(localFilePath))
       {
           return false;
       }

       //校验路径是否存在
       if (!TryCreateDirectory(ftpSavePath, userName, password))
           return false;

       try
       {
           FileInfo fileInfo = new FileInfo(localFilePath);

           // 创建ftp请求
           FtpWebRequest request = (FtpWebRequest)WebRequest.Create(ftpSavePath + ftpFileName);
           request.Method = WebRequestMethods.Ftp.UploadFile;
           request.Credentials = new NetworkCredential(userName, password);
           request.UseBinary = true;
           request.KeepAlive = false; // 上传完成后关闭连接
           request.Timeout = 300000; // 5分钟超时

           // ✅ 使用流式传输，避免内存溢出
           using (FileStream fileStream = new FileStream(localFilePath, FileMode.Open, FileAccess.Read))
           using (Stream requestStream = request.GetRequestStream())
           {
               byte[] buffer = new byte[128 * 1024]; // 64KB缓冲区
               int bytesRead;
               long totalBytes = 0;
               DateTime lastLogTime = DateTime.Now;

               while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) > 0)
               {
                   requestStream.Write(buffer, 0, bytesRead);
                   totalBytes += bytesRead;

                   // 每10秒记录一次上传进度（可选）
                   if ((DateTime.Now - lastLogTime).TotalSeconds >= 10)
                   {
                       double progress = (double)totalBytes / fileInfo.Length * 100;
                       lastLogTime = DateTime.Now;
                   }
               }
           }
       }
       catch (Exception ex)
       {
           return false;
       }

       return true;
   }
   /// <summary>
   /// 校验ftp目录是否存在
   /// </summary>
   /// <param name="directoryUri"></param>
   /// <param name="username"></param>
   /// <param name="password"></param>
   /// <returns></returns>
   public static bool TryCreateDirectory(string directoryUri, string username, string password)
   {
       try
       {
           // 创建 FTP 请求以检查目录
           FtpWebRequest request = (FtpWebRequest)WebRequest.Create(directoryUri);
           request.Method = WebRequestMethods.Ftp.ListDirectory;
           request.Credentials = new NetworkCredential(username, password);

           // 尝试获取目录列表
           using FtpWebResponse response = (FtpWebResponse)request.GetResponse();
       }
       catch (WebException ex)
       {
           // 如果目录不存在，则会抛出异常
           if (ex.Response is FtpWebResponse response && response.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable)
           {
               // 创建目录
               FtpWebRequest createDirRequest = (FtpWebRequest)WebRequest.Create(directoryUri);
               createDirRequest.Method = WebRequestMethods.Ftp.MakeDirectory;
               createDirRequest.Credentials = new NetworkCredential(username, password);

               using var createResponse = (FtpWebResponse)createDirRequest.GetResponse();
           }
           else
           {
               //其他异常
               return false;
           }
       }
       catch (Exception ex) 
       {
           return false;
       }

       return true;
   }
   

    public async Task Test()
    {
        string ip = "172.18.18.200";
        int port = 21;
        string userName = "ftpuser";
        string pwd = "ftpuser";

        FluentFTP.AsyncFtpClient ftp = new FluentFTP.AsyncFtpClient(ip, userName, pwd, port)
        {
            Config = new FluentFTP.FtpConfig
            {
                ConnectTimeout = 5000,  //连接超时，单位为毫秒
                DataConnectionConnectTimeout = 5000, //数据连接超时，单位为毫秒
                DataConnectionReadTimeout = 5000, //数据读取超时，单位为毫秒
                ReadTimeout = 5000, //读取超时，单位为毫秒
                RetryAttempts = 3 //重试次数
            }
        };

        //开始连接FTP服务器
        await ftp.Connect();

        // 检查目录是否存在，如果不存在则创建
        if (! await ftp.DirectoryExists("wtTest"))
        {
            await ftp.CreateDirectory("wtTest");
        }

        // 上传文件
        await ftp.UploadFile(@"C:\Users\Htkw\Desktop\111\1.jpg", "wtTest/test.jpg");

        // 下载文件
        await ftp.DownloadFile(@"C:\Users\Htkw\Desktop\111\downloaded_test.jpg", "wtTest/test.jpg");



        await ftp.Disconnect(); //关闭连接
        await ftp.DisposeAsync(); //释放资源
    }