http://www.cnblogs.com/zcttxs/archive/2012/05/21/2511947.html
http://www.cnblogs.com/flashlm/archive/2009/07/25/file_stream_write_method.html
http://www.cnblogs.com/liang--liang/archive/2012/10/20/2732745.html
一、MVC下载
方式一:
public FileStreamResult DownFile(string filePath, string fileName)
{
string absoluFilePath = Server.MapPath(System.Configuration.ConfigurationManager.AppSettings["AttachmentPath"] + filePath);
return File(new FileStream(absoluFilePath, FileMode.Open), "application/octet-stream", Server.UrlEncode(fileName));
}
方式二:
public ActionResult DownFile(string filePath, string fileName)
{
filePath = Server.MapPath(System.Configuration.ConfigurationManager.AppSettings["AttachmentPath"] + filePath);
FileStream fs = new FileStream(filePath, FileMode.Open);
byte[] bytes = new byte[(int)fs.Length];
fs.Read(bytes, 0, bytes.Length);
fs.Close();
Response.Charset = "UTF-8";
Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8");
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition", "attachment; filename=" + Server.UrlEncode(fileName));
Response.BinaryWrite(bytes);
Response.Flush();
Response.End();
return new EmptyResult();
}
View调用:
<a href="/Document/DownFile?filePath=@item.Value&fileName=@item.Key">下载</a>
二、其他下载
aspx页面:


<%@ Page Language="C#" AutoEventWireup="true" CodeFile="上传和下载文件.aspx.cs" Inherits="上传和下载文件" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>无标题页</title>
</head>
<body>
<form id="form1" runat="server">
<asp:FileUpload ID="homeworkFile" runat="server" />
<asp:Button ID="btnAdd" runat="server" Text="上传" OnClick="btnAdd_Click"/></br>
<asp:Button ID="btndownfile" runat="server" Text="下载方法一:TransmitFile"
onclick="btndownfile_Click" /></br>
<asp:Button ID="btndownfilebyWriteFile" runat="server"
Text="下载方法二:WriteFile" onclick="btndownfilebyWriteFile_Click" /></br>
<asp:Button ID="btndownfilebyWriteFile2" runat="server"
Text="下载方法三:WriteFile分块" onclick="btndownfilebyWriteFile2_Click" /><br />
<asp:Button ID="btndownfilebystream" runat="server" Text="下载方法四:流方式下载"
onclick="btndownfilebystream_Click" />
</form>
</body>
</html>
View Code
aspx后台代码:


using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;
public partial class 上传和下载文件 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnAdd_Click(object sender, EventArgs e)
{
//文件原名
string fileName = Path.GetFileName(this.homeworkFile.FileName);
//文件新名字=文件原名+当前时间
string newFileName = fileName.Substring(0, fileName.IndexOf('.')) + DateTime.Now.ToString("yyyyMMddhhmmss");
//给文件名加后缀名
newFileName += fileName.Substring(fileName.IndexOf('.'), fileName.Length - fileName.IndexOf('.'));
//获得文件存储的路径名
string Url = ConfigurationManager.AppSettings["ResoursePath"] + ConfigurationManager.AppSettings["RESHomeworkContentPath"] + @"\" + newFileName;
//验证文件大小
if (this.IsFileSizeLessMax())
{ //验证文件的类型
if (this.isTypeOk(Url))
{
//验证文件存储的路径是否存在
string pathStr = ConfigurationManager.AppSettings["ResoursePath"] + ConfigurationManager.AppSettings["RESHomeworkContentPath"];
if (!Directory.Exists(pathStr)) //如果不存在路径
{
Directory.CreateDirectory(pathStr); //创建路径
}
if (!Url.Equals("")) //如果有上传文件
{
FileUpload fileUpLoad = new FileUpload();
//1.存放文件
// fileUpLoad.SaveAs(Url);
homeworkFile.PostedFile.SaveAs(Url);
}
}
}
}
/// <summary>
/// 验证上传文件是否超过规定的最大值
/// </summary>
/// <returns></returns>
private bool IsFileSizeLessMax()
{
//返回值
bool result = false;
if (this.homeworkFile.HasFile) //如果上传了文件
{
//获取上传文件的允许最大值
long fileMaxSize = 1024 * 1024;
try
{
fileMaxSize *= int.Parse(ConfigurationManager.AppSettings["FileUploadMaxSize"].Substring(0, ConfigurationManager.AppSettings["FileUploadMaxSize"].Length - 1));
}
catch (Exception ex)
{
//this.WriteException("UserPotal:Homework", ex);
}
if (this.homeworkFile.PostedFile.ContentLength > int.Parse(fileMaxSize.ToString())) //如果文件大小超过规定的最大值
{
//this.ShowMessage("文件超过规定大小。");
}
else
{
result = true;
}
}
else //如果没有上传的文件
{
result = true;
}
return result;
}
/// <summary>
/// 验证文件类型的方法
/// </summary>
/// <param name="fileName"></param>
/// <returns></returns>
private bool isTypeOk(string fileName)
{
//返回结果
bool endResult = false;
//验证结果
int result = 0;
if (!fileName.Equals("")) //如果有上传文件
{
//允许的文件类型
string[] fileType = null;
try
{
fileType = ConfigurationManager.AppSettings["FileType"].Split(',');
}
catch (Exception ex)
{
//this.ShowMessage("获取配置文件信息出错");
//this.WriteException("AdminProtal:Homework", ex);
}
fileName = fileName.Substring(fileName.LastIndexOf('.'), fileName.Length - fileName.LastIndexOf('.'));
for (int i = 0; i < fileType.Length; i++)
{
if (fileType[i].Equals(fileName)) //如果是合法文件类型
{
result++;
}
}
if (result > 0)
{
endResult = true;
}
}
else //如果没有上传文件
{
endResult = true;
}
return endResult;
}
//下载方法一
protected void btndownfile_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=DBintegrate20120521030107.txt");
string filename = Server.MapPath("BJNetwork/Data/DBintegrate20120521030107.txt");
Response.TransmitFile(filename);
}
//下载方法二
protected void btndownfilebyWriteFile_Click(object sender, EventArgs e)
{
/* using System.IO; */
string fileName = "DBintegrate20120521030107.txt";//客户端保存的文件名
string filePath = Server.MapPath("BJNetwork/Data/DBintegrate20120521030107.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();
}
//下载方法三
protected void btndownfilebyWriteFile2_Click(object sender, EventArgs e)
{
string fileName = "前台老师和学生界面对比20120521034329.rar";//客户端保存的文件名
string filePath = Server.MapPath("BJNetwork/Data/前台老师和学生界面对比20120521034329.rar");//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 byte[ChunkSize];
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();
}
}
//下载方法四
protected void btndownfilebystream_Click(object sender, EventArgs e)
{
string fileName = "前台老师和学生界面对比20120521034329.rar";//客户端保存的文件名
string filePath = Server.MapPath("BJNetwork/Data/前台老师和学生界面对比20120521034329.rar");//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();
}
}
View Code
web配置文件:
<appSettings>
<!--上传文件的路径-->
<add key="ResoursePath" value="D:\IbeaconShow\BJNetwork"/>
<add key="RESHomeworkContentPath" value="\Data"/>
<!--可上传文件的大小-->
<add key="FileUploadMaxSize" value="20M"/>
<!--可上传文件类型 -->
<add key="FileType" value=".zip,.txt,.doc,.rar,.xls,.rtf,.xlsx,.docx,.png"/>
</appSettings>
<system.web>
<!--修改asp.net默认上传文件的大小-->
<httpRuntime executionTimeout="300" maxRequestLength="409600" useFullyQualifiedRedirectUrl="false"/>
</system.web>
IIS中上传大小的修改
1、首先要到进程中把IIS服务关了,即把inetinfo.exe进程关了,不然里面的文件不给你更改的哟~~~
2、在系统目录中找到:windows/system32/inesrv/metabase.xml”文件,找个文本编辑器打开他,我都用
EditPuls(这家伙不错,带字体色彩的),Ctrl+F
找到AspMaxRequestEntityAllowed="204800"这一项,这就是iis上传文件的默认大小了,默认为204800Byte,
也就是200KB,将它改为你需要的大小就可以了!
asp.net里提供了多种方式,从服务器端向客户端写文件流,实现客户端下载文件。这种技术在做防下载系统时比较有用处。
主些技术主要有:WriteFile、TransmitFile和BinaryWrite
其中WriteFilet和BinaryWrite出现得比较早,对文件流的输出可以启动作用,但由于都是将整个文件读到内存后再往客户端写,因此会占用大量的内存资源,特别是要下载的文件比较大时,影响asp.net应用的稳定运行。
TransmitFile是为了弥补WriteFile和BinaryWrite的不足才出现的方法,比WriteFile和BinaryWrite更加的稳定强大,对大文件的支持也不错。但其也有不足之处,对断点续传的支持不行,一个大的文件如果一次性没有下载完成的话,就需要从头再来。
那么一个对性能影响小、支持大文件下载、支持断点续传甚至是多线程下载程序还是需要自己来写的。其实BinaryWrite和WriteFile之所以会影响性能,是因为将整个文件读到内存后再往客户端写,那么我们可以控制他的输出方式,一次只读一块内容到内存,再往客户端写,这些就可以自定义下载的和个细节了。下面提供一个相对不错的下载函数供大家参考。
/// <summary>
/// 下载文件,支持大文件、续传、速度限制。支持续传的响应头Accept-Ranges、ETag,请求头Range 。
/// Accept-Ranges:响应头,向客户端指明,此进程支持可恢复下载.实现后台智能传输服务(BITS),值为:bytes;
/// ETag:响应头,用于对客户端的初始(200)响应,以及来自客户端的恢复请求,
/// 必须为每个文件提供一个唯一的ETag值(可由文件名和文件最后被修改的日期组成),这使客户端软件能够验证它们已经下载的字节块是否仍然是最新的。
/// Range:续传的起始位置,即已经下载到客户端的字节数,值如:bytes=1474560- 。
/// 另外:UrlEncode编码后会把文件名中的空格转换中+(+转换为%2b),但是浏览器是不能理解加号为空格的,所以在浏览器下载得到的文件,空格就变成了加号;
/// 解决办法:UrlEncode 之后, 将 "+" 替换成 "%20",因为浏览器将%20转换为空格
/// </summary>
/// <param name="httpContext">当前请求的HttpContext</param>
/// <param name="filePath">下载文件的物理路径,含路径、文件名</param>
/// <param name="speed">下载速度:每秒允许下载的字节数</param>
/// <returns>true下载成功,false下载失败</returns>
public static bool DownloadFile(HttpContext httpContext, string filePath, long speed)
{
httpContext.Response.Clear();
bool ret = true;
try
{
#region --验证:HttpMethod,请求的文件是否存在
switch (httpContext.Request.HttpMethod.ToUpper())
{ //目前只支持GET和HEAD方法
case "GET":
case "HEAD":
break;
default:
httpContext.Response.StatusCode = 501;
return false;
}
if (!File.Exists(filePath))
{
httpContext.Response.StatusCode = 404;
return false;
}
#endregion
#region 定义局部变量
long startBytes = 0;
long stopBytes = 0;
int packSize = 1024 * 10; //分块读取,每块10K bytes
string fileName = Path.GetFileName(filePath);
FileStream myFile = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
BinaryReader br = new BinaryReader(myFile);
long fileLength = myFile.Length;
int sleep = (int)Math.Ceiling(1000.0 * packSize / speed);//毫秒数:读取下一数据块的时间间隔
string lastUpdateTiemStr = File.GetLastWriteTimeUtc(filePath).ToString("r");
string eTag = HttpUtility.UrlEncode(fileName, Encoding.UTF8) + lastUpdateTiemStr;//便于恢复下载时提取请求头;
#endregion
#region --验证:文件是否太大,是否是续传,且在上次被请求的日期之后是否被修改过
if (myFile.Length > long.MaxValue)
{//-------文件太大了-------
httpContext.Response.StatusCode = 413;//请求实体太大
return false;
}
if (httpContext.Request.Headers["If-Range"] != null)//对应响应头ETag:文件名+文件最后修改时间
{
//----------上次被请求的日期之后被修改过--------------
if (httpContext.Request.Headers["If-Range"].Replace("\"", "") != eTag)
{//文件修改过
httpContext.Response.StatusCode = 412;//预处理失败
return false;
}
}
#endregion
try
{
#region -------添加重要响应头、解析请求头、相关验证
httpContext.Response.Clear();
if (httpContext.Request.Headers["Range"] != null)
{//------如果是续传请求,则获取续传的起始位置,即已经下载到客户端的字节数------
httpContext.Response.StatusCode = 206;//重要:续传必须,表示局部范围响应。初始下载时默认为200
string[] range = httpContext.Request.Headers["Range"].Split(new char[] { '=', '-' });//"bytes=1474560-"
startBytes = Convert.ToInt64(range[1]);//已经下载的字节数,即本次下载的开始位置
if (startBytes < 0 || startBytes >= fileLength)
{//无效的起始位置
return false;
}
if (range.Length == 3)
{
stopBytes = Convert.ToInt64(range[2]);//结束下载的字节数,即本次下载的结束位置
if (startBytes < 0 || startBytes >= fileLength)
{
return false;
}
}
}
httpContext.Response.Buffer = false;
httpContext.Response.AddHeader("Content-MD5", FileHash.MD5File(filePath));//用于验证文件
httpContext.Response.AddHeader("Accept-Ranges", "bytes");//重要:续传必须
httpContext.Response.AppendHeader("ETag", "\"" + eTag + "\"");//重要:续传必须
httpContext.Response.AppendHeader("Last-Modified", lastUpdateTiemStr);//把最后修改日期写入响应
httpContext.Response.ContentType = "application/octet-stream";//MIME类型:匹配任意文件类型
httpContext.Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(fileName, Encoding.UTF8).Replace("+", "%20"));
httpContext.Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());
httpContext.Response.AddHeader("Connection", "Keep-Alive");
httpContext.Response.ContentEncoding = Encoding.UTF8;
if (startBytes > 0)
{//------如果是续传请求,告诉客户端本次的开始字节数,总长度,以便客户端将续传数据追加到startBytes位置后----------
httpContext.Response.AddHeader("Content-Range", string.Format("bytes {0}-{1}/{2}", startBytes, fileLength - 1, fileLength));
}
#endregion
#region -------向客户端发送数据块-------------------
br.BaseStream.Seek(startBytes, SeekOrigin.Begin);
int maxCount = (int)Math.Ceiling((fileLength - startBytes + 0.0) / packSize);//分块下载,剩余部分可分成的块数
for (int i = 0; i < maxCount && httpContext.Response.IsClientConnected; i++)
{//客户端中断连接,则暂停
httpContext.Response.BinaryWrite(br.ReadBytes(packSize));
httpContext.Response.Flush();
if (sleep > 1) Thread.Sleep(sleep);
}
#endregion
}
catch
{
ret = false;
}
finally
{
br.Close();
myFile.Close();
}
}
catch
{
ret = false;
}
return ret;
}