上传文件.下载文件(转)

protected void ResponseFile(string path)
{
System.IO.Stream iStream = null;
byte[] buffer = new Byte[10000];
int length;
long dataToRead;
string filename = System.IO.Path.GetFileName(path);

try
{
iStream= new System.IO.FileStream(path, System.IO.FileMode.Open,
System.IO.FileAccess.Read, System.IO.FileShare.Read);
dataToRead= iStream.Length;
Response.ContentType= "application/octet-stream";
Response.AddHeader("Content-Disposition", "attachment; filename=" +
HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8));
while (dataToRead > 0)
{
if (Response.IsClientConnected)
{
length= iStream.Read(buffer, 0, 10000);
Response.OutputStream.Write(buffer,0, length);
Response.Flush();

buffer= new Byte[10000];
dataToRead= dataToRead - length;
}
else
{
dataToRead= -1;
}
}
}
catch (Exception ex)
{
Response.Write("文件下载时出现错误!");
}
finally
{
if (iStream != null)
{
iStream.Close();
}
}
}

2.防止盗链

protected void Page_Load(object sender, EventArgs e) 
{ 
 /*--------------------------------------------------------------*\ 
* 大文件下载，防盗链 * 
* * 
* tda7264@163.com * 
* * 
* 飘遥的BLOG http://xianfen.net * 
\* -------------------------------------------------------------*/ 
 
 if (Request.QueryString["FileName"] == null) 
{ 
InvalidRedirect(); 
} 
 
 string fileName = Request.QueryString["FileName"]; 
 
 if (fileName == string.Empty) 
{ 
InvalidRedirect(); 
} 
 
 //判断配置文件是否直接下载                   
    string downDirect = ConfigurationManager.AppSettings["Down"].ToLower(); 
 
 if (downDirect == "true") 
{ 
UpdateHits(fileName);//更新下载次数 
        Response.Redirect("Upload/" + fileName); 
 return; 
} 
 
 string path = Server.MapPath(Request.ApplicationPath + "/Upload/" + fileName); 
 string referrer = string.Empty; 
 
 if (Request.UrlReferrer != null) 
{ 
referrer= Request.UrlReferrer.ToString().ToLower(); 
} 
 
 string d = ConfigurationManager.AppSettings["Valid"].ToLower(); 
 string[] domainName = 
ConfigurationManager.AppSettings["Refers"].ToLower().Split(new char[] { ',' }); 
 
 // 如果设置为防止盗链，判断访问来源是否合法 
    if (d == "false") 
{ 
 foreach (string s in domainName) 
{ 
 if (referrer.IndexOf(s.ToLower()) > 0) 
{ 
UpdateHits(fileName);//更新下载次数 
 ResponseFile(path); 
 return; 
} 
} 
 
InvalidRedirect(); 
} 
 else 
{ 
ResponseFile(path); 
} 
} 
 
protected void UpdateHits(string fileName) 
{ 
 //更新文件下载次数的代码 
} 
 
protected void InvalidRedirect() 
{ 
 string defaultPage = ConfigurationManager.AppSettings["DefaultRedirect"]; 
 
Response.Redirect(defaultPage,true); 
}

3.配置文件
配置文件中配置下载方式、盗链功能是否开启及盗链默认转向的页面地址：

<appSettings> 
 <add key="Down" value="false"/> 
 <!--是否直接下载--> 
 <add key="Valid" value="false"/> 
 <!--是否允许盗链--> 
 <add key="Refers" value="localhost,google.cn"/> 
 <!--多个允许的访问来源用半角的","分割--> 
 <add key="DefaultRedirect" value="Error.htm"/> 
 <!--默认转向的页面--> 
</appSettings>