在浏览器中从FTP下载文件

public static class FTPHelper
{
/// <summary>
/// 得到特定FTP目录的文件列表
/// </summary>
/// <param name="uri">ftp://{username}:{password}@ftp.baidu.com/{folderName}</param>
public static List<String> ListFiles(Uri serverUri)
{
// The serverUri parameter should start with the ftp:// scheme.
if (serverUri.Scheme != Uri.UriSchemeFtp)
{
throw new ArgumentException("uri must be ftp scheme");
} FtpWebRequest ftpRequest = null;
StreamReader reader = null;
try
{
// Get the object used to communicate with the server.
ftpRequest = (FtpWebRequest)FtpWebRequest.Create(serverUri); ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory; reader = new StreamReader(ftpRequest.GetResponse().GetResponseStream(), Encoding.Default); //read data.
List<String> fileNames = new List<String>();
string line = reader.ReadLine();
while (line != null)
{ fileNames.Add(line);
line = reader.ReadLine();
} return fileNames; }
catch(Exception ex)
{
throw ex;
}
finally
{
if(reader != null)
{
reader.Close();
}
if (ftpRequest != null)
{
ftpRequest.Abort();
}
}
} /// <summary>
/// 得到特定文件的大小
/// </summary>
/// <param name="uri">ftp://{username}:{password}@ftp.baidu.com/{fileName}</param>
public static long GetFileSize(Uri serverUri)
{
// The serverUri parameter should start with the ftp:// scheme.
if (serverUri.Scheme != Uri.UriSchemeFtp)
{
throw new ArgumentException("uri must be ftp scheme");
} FtpWebRequest ftpRequest = null;
StreamReader reader = null;
try
{
// Get the object used to communicate with the server.
ftpRequest = (FtpWebRequest)FtpWebRequest.Create(serverUri); ftpRequest.Method = WebRequestMethods.Ftp.GetFileSize; return ftpRequest.GetResponse().ContentLength;
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (reader != null)
{
reader.Close();
}
if (ftpRequest != null)
{
ftpRequest.Abort();
}
}
}
}

/// <summary>
/// 下载文件（此方法定义在实现Controller某类的某个MVC Controller中）
/// </summary>
/// <param name="uri"></param>
public void DownLoadFile(Uri uri,string fileName)
{
//Create a stream for the file
Stream stream = null; //This controls how many bytes to read at a time and send to the client
int bytesToRead = ; // Buffer to read bytes in chunk size specified above
byte[] buffer = new Byte[bytesToRead]; // The number of bytes read
try
{
long fileSize = FTPHelper.GetFileSize(uri);
//Create a WebRequest to get the file
FtpWebRequest fileReq = (FtpWebRequest)FtpWebRequest.Create(uri); //Create a response for this request
FtpWebResponse fileResp = (FtpWebResponse)fileReq.GetResponse(); //Get the Stream returned from the response
stream = fileResp.GetResponseStream(); // prepare the response to the client. resp is the client Response
var resp = HttpContext.Response; //Indicate the type of data being sent
resp.ContentType = "application/octet-stream"; //Name the file
resp.AddHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
resp.AddHeader("Content-Length", fileSize.ToString()); int length;
do
{
// Verify that the client is connected.
if (resp.IsClientConnected)
{
// Read data into the buffer.
length = stream.Read(buffer, , bytesToRead); // and write it out to the response's output stream
resp.OutputStream.Write(buffer, , length); // Flush the data
resp.Flush(); //Clear the buffer
buffer = new Byte[bytesToRead];
}
else
{
// cancel the download if client has disconnected
length = -;
}
} while (length > ); //Repeat until no data is read
}
finally
{
if (stream != null)
{
//Close the input stream
stream.Close();
}
}
}