大文件上传之FTP文件上传

我想很多人都知道.net自带的上传控件是不支持大文件上传的,默认情况下是4M,当然你可以通过配置WEB.CONFIG来增大上传大小,但是会影响服务器的性能.

这里就大文件上传提供一个解决方案,就是采用FTP上传,FTP协议是支持大文件上传的.再大的都吃得消.因此,我们的目的就是再服务器上配置好FTP服务器.然后上传文件就交给FTP服务器来完成.可以手动在DOS中操作FTP服务器.也可以用代码来操作,下面是一个代码的例子,摘录自MSDN:

FTPState.cs:


using System;


using System.Data;


using System.Configuration;


using System.Threading;


using System.Net;






/**//// <summary>


/// FTPState 的摘要说明


/// </summary>


public class FTPState




...{


private ManualResetEvent wait;




private FtpWebRequest request;




private string fileName;




private Exception operationException = null;




string status;




public FTPState()




...{


wait = new ManualResetEvent(false);


}




public ManualResetEvent OperationComplete




...{




get ...{ return wait; }


}




public FtpWebRequest Request




...{


get




...{


return request;


}


set




...{


request = value;


}


}


public string FileName




...{




get ...{ return fileName; }




set ...{ fileName = value; }


}




public Exception OperationException




...{




get ...{ return operationException; }




set ...{ operationException = value; }


}




public string StateDescription




...{




get ...{ return status; }




set ...{ status = value; }


}


}



FTPsupport.cs:


using System;


using System.Data;


using System.Configuration;




using System.Net;


using System.IO;


using System.Threading;






/**//// <summary>


/// FTPsupport 的摘要说明


/// </summary>


public class FTPsupport




...{


public FTPsupport()




...{


//


// TODO: 在此处添加构造函数逻辑


//


}


public static bool ListFilesOnServer(Uri serverUri,ref string message,ref Stream responseStream)




...{


// The serverUri should start with the ftp:// scheme.


if (serverUri.Scheme != Uri.UriSchemeFtp)




...{


return false;


}


// Get the object used to communicate with the server.


FtpWebRequest request = (FtpWebRequest)WebRequest.Create(serverUri);


request.Method = WebRequestMethods.Ftp.ListDirectory;




// Get the ServicePoint object used for this request, and limit it to one connection.


// In a real-world application you might use the default number of connections (2),


// or select a value that works best for your application.




ServicePoint sp = request.ServicePoint;


//Console.WriteLine("ServicePoint connections = {0}.", sp.ConnectionLimit);


sp.ConnectionLimit = 1;




FtpWebResponse response = (FtpWebResponse)request.GetResponse();


//Stream responseStream = null;


// The following streams are used to read the data returned from the server.


StreamReader readStream = null;


try




...{


responseStream = response.GetResponseStream();


readStream = new StreamReader(responseStream, System.Text.Encoding.UTF8);




if (readStream != null)




...{


// Display the data received from the server.


//Console.WriteLine(readStream.ReadToEnd());


message = readStream.ReadToEnd();


}


//Console.WriteLine("List status: {0}", response.StatusDescription);


}


finally




...{


//if (readStream != null)


//{


// readStream.Close();


//}


if (response != null)




...{


response.Close();


}


}




return true;


}


public static bool DelFile(Uri serverUri,ref string result)




...{


if(serverUri.Scheme!=Uri.UriSchemeFtp)




...{


return false;


}


FtpWebRequest request = (FtpWebRequest)WebRequest.Create(serverUri);




request.Method = WebRequestMethods.Ftp.DeleteFile;




FtpWebResponse response = (FtpWebResponse)request.GetResponse();




result = response.StatusDescription;




response.Close();




return true;


}


public static bool FileDownload1(Uri serverUri,ref string content,ref Stream filestream)




...{


if(serverUri.Scheme!=Uri.UriSchemeFtp)




...{


return false;


}


FtpWebRequest request = (FtpWebRequest)WebRequest.Create(serverUri);




request.Method = WebRequestMethods.Ftp.DownloadFile;




FtpWebResponse response = (FtpWebResponse)request.GetResponse();




filestream = response.GetResponseStream();




StreamReader reader = new StreamReader(filestream, System.Text.Encoding.UTF8);




content = reader.ReadToEnd();




response.Close();




return true;


}


public static bool FileDownload(Uri serverUri,ref string filestring)




...{


if (serverUri.Scheme != Uri.UriSchemeFtp)




...{


return false;


}




WebClient request = new WebClient();




request.Credentials = new NetworkCredential("anonymous", "xiao_jun_0820@163.com");




try




...{


byte[] newFileData = request.DownloadData(serverUri);




//这里ref回去的是下载的文件的内容,然后在前台新建一个同类型的文件,把内容写进去就OK了.


filestring = System.Text.Encoding.UTF8.GetString(newFileData);//这个地方可能会有点问题,如果你要下载的文件不是UTF-8形式保存的,则文件内容中的中文将变乱码,那就只能预先将FTP服务器上的文件保存为UTF-8形式.


}


catch(WebException e)




...{


filestring = e.ToString();


}


return true;


}




public static bool FileUpLoad(string fileName,Uri serverUri)




...{


ManualResetEvent waitObject;




FTPState state = new FTPState();




FtpWebRequest request = (FtpWebRequest)WebRequest.Create(serverUri);


request.Method = WebRequestMethods.Ftp.UploadFile;


request.Credentials = new NetworkCredential("anonymous", "xiao_jun_0820@163.com");




state.FileName = fileName;


state.Request = request;




waitObject=state.OperationComplete;




state.Request.BeginGetRequestStream(new AsyncCallback(EndGetStreamCallback),state);




waitObject.WaitOne();




if (state.OperationException != null)




...{


throw state.OperationException;


return false;




}


else




...{


return true;


}






}




private static void EndGetStreamCallback(IAsyncResult ar)




...{


FTPState state = (FTPState)ar.AsyncState;




Stream requestStream;




try




...{


requestStream = state.Request.EndGetRequestStream(ar);




const int buffLength = 2048;


byte[] buffer = new byte[buffLength];


int count = 0;


int readBytes = 0;


FileStream stream = File.OpenRead(state.FileName);


do




...{


readBytes = stream.Read(buffer, 0, buffLength);


requestStream.Write(buffer, 0, readBytes);


count += readBytes;


}


while (readBytes != 0);


//发送请求之前关闭该请求流


requestStream.Close();




state.Request.BeginGetResponse(new AsyncCallback(EndGetResponseCallback), state);


}


catch (Exception e)




...{


state.OperationException = e;


state.OperationComplete.Set();


return;


}




}




private static void EndGetResponseCallback(IAsyncResult ar)




...{


FTPState state = (FTPState)ar.AsyncState;




FtpWebResponse response = null;




try




...{


response = (FtpWebResponse)state.Request.EndGetResponse(ar);


response.Close();


state.StateDescription = response.StatusDescription;


state.OperationComplete.Set();


}


catch (Exception e)




...{


state.OperationException = e;


state.OperationComplete.Set();


}




}


}



这两个类我稍微做了点点修改,原文请查看MSDN.