Question

我正在尝试使用c＃中的FTP从远程计算机下载文件，但是它不起作用。当我使用f10来使用GetResponse方法时，引发了异常。它说：“无法连接到远程服务器”，它看起来像是关于连接问题，但不是。

当我在ContentType和PreAuthenticate代码中创建请求时，抛出异常并说：“ System.NotSupportedException”

我该如何解决？有什么想法吗？

这是FTP的连接信息。

private static string host = @"ftp://XXX.XX.XXX.XX/";
private static string user = "XXXXXXXX";
private static string pass = "XXXXXXXX";
private static string localfile = @"E:/Files/Attachment";
private static string remoteFile = @"D:/log/stdlog.6.txt";

然后是FTP类

public class FtpServer
{
    private string host = null;
    private string user = null;
    private string pass = null;
    private FtpWebRequest ftpRequest = null;
    private FtpWebResponse ftpResponse = null;
    private Stream ftpStream = null;
    private int bufferSize = 2048;

    /* Construct Object */
    public FtpServer(string hostIP, string userName, string password) { host = hostIP; user = userName; pass = password; }
    public  void Download(string remoteFile, string localFile)
    {

        try
        {

            ftpRequest = (FtpWebRequest)FtpWebRequest.Create(host+remoteFile);


            ftpRequest.Credentials = new NetworkCredential(user,pass);

            ftpRequest.UseBinary = true;
            ftpRequest.UsePassive = true;
            ftpRequest.KeepAlive = true;

            ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;

            ftpResponse = (FtpWebResponse)ftpRequest.GetResponse();

            ftpStream = ftpResponse.GetResponseStream();

            FileStream localFileStream = new FileStream(localFile, FileMode.Create);

            byte[] byteBuffer = new byte[bufferSize];
            int bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);

            try
            {
                while (bytesRead > 0)
                {
                    localFileStream.Write(byteBuffer, 0, bytesRead);
                    bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }

            localFileStream.Close();
            ftpStream.Close();
            ftpResponse.Close();
            ftpRequest = null;
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return;
    }
}

Answer 1

无法连接到远程服务器可能有几个原因。

1），您可能会错误地键入服务器地址并指向不存在的地址。

2）服务器暂时关闭或关闭，您无法访问它。

3）您为服务器输入了错误的凭据。

无论哪种方式，我建议您在代码中实现using statement，而不要在每个流上使用close()：

ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;

    using (ftpResponse = (FtpWebResponse)ftpRequest.GetResponse())
    {
        using (ftpStream = ftpResponse.GetResponseStream())
        {

            using (FileStream localFileStream = new FileStream(localFile, FileMode.Create))
            {

                byte[] byteBuffer = new byte[bufferSize];
                int bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);

                try
                {
                    while (bytesRead > 0)
                    {
                        localFileStream.Write(byteBuffer, 0, bytesRead);
                        bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
                     }
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine(ex.ToString());
                 }

            }
        }
    }

ftpRequest = null;

FTP下载文件

1 个答案: