文件下载的几种方式.docx
文件下载的几种方式先把有问题的代码贴出来吧, using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.IO; namespace infoPlatClient.NetDisk public partial class downLoad : Com.DRPENG.Common.WebStruct.BaseForm / <summary> / 取得要下载文件的路径 / </summary> private string fileRpath get return Request"fileRpath" = null ? "" : Request"fileRpath" / <summary> / 取得要下载文件的名称 / </summary> protected void Page_Load(object sender, EventArgs e) if (!IsPostBack) this.DownloadFile; public void DownloadFile Response.ClearHeaders; Response.Clear; Response.Expires = 0; Response.Buffer =true; Response.AddHeader("Accept-Language", "zh-tw"); string name = System.IO.Path.GetFileName(fileRpath); System.IO.FileStream files = new FileStream(fileRpath, FileMode.Open, FileAccess.Read, FileShare.Read); byte byteFile=null; if (files.Length = 0) byteFile=new byte1; else byteFile = new bytefiles.Length; files.Read(byteFile, 0, (int)byteFile.Length); files.Close; Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(name, System.Text.Encoding.UTF8); Response.ContentType = "application/octet-stream;charset=gbk" Response.BinaryWrite(byteFile); Response.End; 之前一直用这种下载方式，可是有一次用户上传了一个700Mb的文件时报内存溢出的问题，分析了一下原因，用户的内存只有256M，而下载文件时要创建内存流，导致了内存溢出。 解决方案:1>WriteFile分块下载，就是每次下载指定数量的多件; 2>通过超链接的方式; lblDownLoad.Text = "<a href='" + drv"VPath".ToString + "'>下载</a>" 下面是四种实现文件下载的方式: using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.IO; public partial class _Default : System.Web.UI.Page protected void Page_Load(object sender, EventArgs e) /TransmitFile实现下载 protected void Button1_Click(object sender, EventArgs e) /* 微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite 下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。 代码如下： */ Response.ContentType = "application/x-zip-compressed" Response.AddHeader("Content-Disposition", "attachment;filename=z.zip"); string filename = Server.MapPath("DownLoad/z.zip"); Response.TransmitFile(filename); /WriteFile实现下载 protected void Button2_Click(object sender, EventArgs e) /* using System.IO; */ string fileName ="asd.txt"/客户端保存的文件名 string filePath=Server.MapPath("DownLoad/aaa.txt");/路径 FileInfo fileInfo = new FileInfo(filePath); Response.Clear; Response.ClearContent; Response.ClearHeaders; Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName); Response.AddHeader("Content-Length", fileInfo.Length.ToString); Response.AddHeader("Content-Transfer-Encoding", "binary"); Response.ContentType = "application/octet-stream" Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312"); Response.WriteFile(fileInfo.FullName); Response.Flush; Response.End; /WriteFile分块下载 protected void Button3_Click(object sender, EventArgs e) string fileName = "aaa.txt"/客户端保存的文件名 string filePath = Server.MapPath("DownLoad/aaa.txt");/路径 System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath); if (fileInfo.Exists = true) const long ChunkSize = 102400;/100K 每次读取文件，只读取100K，这样可以缓解服务器的压力 byte buffer = new byteChunkSize; Response.Clear; System.IO.FileStream iStream = System.IO.File.OpenRead(filePath); long dataLengthToRead = iStream.Length;/获取下载的文件总大小 Response.ContentType = "application/octet-stream" Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName); while (dataLengthToRead > 0 && Response.IsClientConnected) int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize);/读取的大小 Response.OutputStream.Write(buffer, 0, lengthRead); Response.Flush; dataLengthToRead = dataLengthToRead - lengthRead; Response.Close; /流方式下载 protected void Button4_Click(object sender, EventArgs e) string fileName = "aaa.txt"/客户端保存的文件名 string filePath = Server.MapPath("DownLoad/aaa.txt");/路径 /以字符流的形式下载文件 FileStream fs = new FileStream(filePath, FileMode.Open); byte bytes = new byte(int)fs.Length; fs.Read(bytes, 0, bytes.Length); fs.Close; Response.ContentType = "application/octet-stream" /通知浏览器下载文件而不是打开 Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8); Response.BinaryWrite(bytes); Response.Flush; Response.End;
