FTP下载,遇501错误

Question

ftp下载 包501错误,说参数有错或无效上代码  public static bool DisplayFileFromServer(Uri serverUri,string pwd)
         {
            // The serverUri parameter should start with the ftp:// scheme.
            if (serverUri.Scheme != Uri.UriSchemeFtp)
            {
                return false;
            }
          
            WebClient request = new WebClient();
           
           //连接
            request.Credentials = new NetworkCredential("forumDB", pwd);
            try
            {
                byte[] newFileData = request.DownloadData(serverUri.ToString());
                string fileString = System.Text.Encoding.UTF8.GetString(newFileData);
                Console.WriteLine(fileString);
            }
            catch (WebException e)
            {
                Console.WriteLine(e.ToString());
            }
            return true;
        }
 static void Main(string[] args)
        {
           // Download(@"c:/","a.txt");
            DisplayFileFromServer(new Uri("ftp://117.79.93.200//13_2_db120617.rar"),"ddddd");
}1.我确定 这个跟目录下确实有这个文件
2.用dos和游览器地址都能访问并下载,是我哪写错了?也希望别人能提供ftp下载代码.

Answer 1

我不肯定是不是没指定命令的原因，你这样试试
public static bool DisplayFileFromServer(Uri serverUri, string pwd)
{
    // The serverUri parameter should start with the ftp:// scheme.
    if (serverUri.Scheme != Uri.UriSchemeFtp)
    {
        return false;
    }    try
    {
        var request = (FtpWebRequest)WebRequest.Create(serverUri);
        request.Method = WebRequestMethods.Ftp.DownloadFile;
        request.Credentials = new NetworkCredential("forumDB", pwd);
        request.UseBinary = true;
        request.KeepAlive = false;
        using (var response = request.GetResponse())
        using (var stream = response.GetResponseStream())
        using (var ms = new MemoryStream())
        {
            var buf = new byte[10240];
            int len = 0;
            while ((len = stream.Read(buf, 0, buf.Length)) > 0)
            {
                ms.Write(buf, 0, len);
            }
            byte[] newFileData = ms.ToArray();
            string fileString = System.Text.Encoding.UTF8.GetString(newFileData);
            Console.WriteLine(fileString);
        }
    }
    catch (WebException e)
    {
        Console.WriteLine(e.ToString());
    }
    return true;
}不过看样子下载下来的是个 rar 文件，GetString 会是乱码

Answer 2

internal static bool FtpDownloadFile(FtpSite ftpSite, Uri url)
{
    if(url == null || url.Scheme == null)
    {
        throw new ArgumentNullException("URL");
    }
    if (FtpSite == null)
    {
        throw new ArgumentNullException("FtpSite");
    }
    if (!Uri.UriSchemeFtp.Equals(url.Scheme, StringComparer.CurrentCultureIgnoreCase))
    {
        throw new NotSupportedException("Only for FTP download!");
    }
    //根据URI创建FtpWebRequest对象
    FtpWebRequest ftpRequest = (FtpWebRequest)FtpWebRequest.Create(url);
    //ftp用户名和密码
    ftpRequest.Credentials = new NetworkCredential(ftpSite.UserName, ftpSite.Password);
    ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;     //指定操作类别
    ftpRequest.UseBinary = true;    //指定数据传输类型
    ftpRequest.KeepAlive = false;   //下载完后不用保持连接
    return SaveAsFile(ftpRequest, upgradeReport.SaveFileName);
}static void SaveAsFile(WebRequest request, string saveName)
{
    WebResponse response = null;
    request.Proxy = null;
    request.Timeout = 60000;    //设置请求超时时间
    //request.CachePolicy = new System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.NoCacheNoStore);
    response = (WebResponse)request.GetResponse();
        using (var responseStream = response.GetResponseStream())
        {
            using (var fs = new FileStream(saveName, FileMode.Create, FileAccess.ReadWrite, FileShare.Read))
            {
                int bufferLength = 2048, offset = 0;
                byte[] buffer = new byte[bufferLength];
                while ((offset = responseStream.Read(buffer, 0, bufferLength)) > 0)
                    fs.Write(buffer, 0, offset);
            }
       }       
}

Answer 3

return SaveAsFile(ftpRequest, upgradeReport.SaveFileName);
=>
SaveAsFile(ftpRequest, upgradeReport.SaveFileName);

Answer 4

static bool SaveAsFile(WebRequest request, string saveName)
        {
            WebResponse response = null;
            request.Proxy = null;
            request.Timeout = 60000;    //设置请求超时时间
            //request.CachePolicy = new System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.NoCacheNoStore);
            try
            {
                response = (WebResponse)request.GetResponse();
                using (var responseStream = response.GetResponseStream())
                {
                    using (var fs = new FileStream(saveName, FileMode.Create, FileAccess.ReadWrite, FileShare.Read))
                    {
                        int bufferLength = 2048, offset = 0;
                        byte[] buffer = new byte[bufferLength];
                        while ((offset = responseStream.Read(buffer, 0, bufferLength)) > 0)
                        {
                            fs.Write(buffer, 0, offset);
                        }
                        fs.Close();
                    }
                }
                return true;
            }
            catch
            {                
                return false;
            }