C#實現(xiàn)文件下載的幾種方式
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先把有問題的代碼貼出來吧 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> /// 取得要下載文件的路徑 /// </summary> private string fileRpath { get { return Request["fileRpath"] == null ? "" : Request["fileRpath"]; } } /// <summary> /// 取得要下載文件的名稱 /// </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 byte[1]; } else { byteFile = new byte[files.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(); } } } 之前一直用這種下載方式，可是有一次用戶上傳了一個700Mb的文件時報內(nèi)存溢出的問題，分析了一下原因，用戶的內(nèi)存只有256M，而下載文件時要創(chuàng)建內(nèi)存流，導(dǎo)致了內(nèi)存溢出。 解決方案:1>WriteFile分塊下載，就是每次下載指定數(shù)量的多件; 2>通過超鏈接的方式; lblDownLoad.Text = "<a href='" + drv["VPath"].ToString() + "'>下載</a>" 下面是四種實現(xiàn)文件下載的方式: 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實現(xiàn)下載 protected void Button1_Click(object sender, EventArgs
e) { /* 微軟為Response對象提供了一個新的方法TransmitFile來解決使用Response.BinaryWrite 下載超過400mb的文件時導(dǎo)致Aspnet_wp.exe進(jìn)程回收而無法成功下載的問題。 代碼如下： */ 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實現(xiàn)下載 protected void Button2_Click(object sender, EventArgs
e) { /* using System.IO; */ string fileName ="asd.txt";//客戶端保存的文件名 string
filePath=Server.MapPath("DownLoad/aaa.txt");//路徑 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分塊下載 protected void Button3_Click(object sender, EventArgs
e) { string fileName = "aaa.txt";//客戶端保存的文件名 string filePath =
Server.MapPath("DownLoad/aaa.txt");//路徑 System.IO.FileInfo fileInfo
= new System.IO.FileInfo(filePath); if (fileInfo.Exists == true) { const long ChunkSize = 102400;//100K 每次讀取文件，只讀取100K，這樣可以緩解服務(wù)器的壓力 byte[] buffer = new byte[ChunkSize]; Response.Clear(); System.IO.FileStream
iStream = System.IO.File.OpenRead(filePath); long dataLengthToRead =
iStream.Length;//獲取下載的文件總大小 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));//讀取的大小 Response.OutputStream.Write(buffer,
0, lengthRead); Response.Flush(); dataLengthToRead =
dataLengthToRead - lengthRead; } Response.Close(); } } //流方式下載 protected void Button4_Click(object sender, EventArgs
e) { string fileName = "aaa.txt";//客戶端保存的文件名 string filePath =
Server.MapPath("DownLoad/aaa.txt");//路徑 //以字符流的形式下載文件 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"; //通知瀏覽器下載文件而不是打開 Response.AddHeader("Content-Disposition", "attachment; filename=" +
HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8)); Response.BinaryWrite(bytes); Response.Flush(); Response.End(); } }
該文章在 2021/1/29 9:47:19 編輯過 |
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