HttpHandler实现简单文件下载

ASP.Net处理Http Request的相关流程

ASP.Net处理Http Request时，使用Pipeline（管道）方式，由各个HttpModule对请求进行处理，然后到达 HttpHandler，HttpHandler处理完之后，仍经过Pipeline中各个HttpModule的处理，最后将HTML发送到客户端浏览器中。

用自定义的HttpHandler来完成文件下载功能

自定义HttpHandler代码:

using System;
using System.Web;
using System.IO;
using System.Web.SessionState;

namespace HttpHandlerSample
{
    public class Downloader : IHttpHandler, IRequiresSessionState
    {
        private HttpRequest Request
        {
            get { return HttpContext.Current.Request; }
        }

        private HttpResponse Response
        {
            get { return HttpContext.Current.Response; }
        }

        private string FileName
        {
            get
            {
                return Request["FileName"].ToString();
            }
        }

        #region IHttpHandler Members

        public bool IsReusable
        {
            get { return true; }
        }

        public void ProcessRequest(HttpContext context)
        {
            string filePath = HttpContext.Current.Server.MapPath("File/" + FileName);

            FileStream fs = new FileStream(filePath, FileMode.Open);
            byte[] fileBytes = new byte[(int)fs.Length];
            fs.Read(fileBytes, 0, fileBytes.Length);
            fs.Close();

            Response.Clear();
            Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8));
            Response.AppendHeader("Content-Length", fileBytes.Length.ToString());
            Response.ContentType = "application/octet-stream";
            Response.OutputStream.Write(fileBytes, 0, fileBytes.Length);
            Response.End();
        }

        #endregion
    }
}

Web.Config 配置:

    <httpHandlers>
      <add verb="*" path="Downloader.dl" type="HttpHandlerSample.Downloader"/>
    </httpHandlers>

使用范例:

    <div>
        <asp:HyperLink ID="HyperLink1"  Text="Word.doc" NavigateUrl="~/Downloader.dl?FileName=Word.doc" runat="server"></asp:HyperLink>
        <br />
        <asp:HyperLink ID="HyperLink2" Text="Text.txt" NavigateUrl="~/Downloader.dl?FileName=Text.txt" runat="server"></asp:HyperLink>
        <br />
        <asp:HyperLink ID="HyperLink3" Text="Excel.xls" NavigateUrl="~/Downloader.dl?FileName=Excel.xls" runat="server"></asp:HyperLink>
    </div>

代码下载:

参考资料:

http://www.rainsts.net/article.asp?id=286

http://blog.csdn.net/dollybol/article/details/6400216