ASP.NET網頁中RAR、DOC、PDF等文件下載功能實例源代碼

之前作asp.net下載功能的時候都是採用:
<a href="http://www.wang0214.com/wgcms">下載</a>
的方式來實現下載。

但後來發現，這種方法存在諸多弊端。至於弊端緣由百度一下就明白了。

因此，下面分享下本身修改完善後，asp.net加密文件下載功能：

 

不想看詳細介紹的直接點擊這裏下載：
開始下載：點擊下載
解壓密碼：www.wang0214.com

一、首先新建一個用於進行下載處理的page頁，如download.aspx，裏面不須要寫任何東西。

 

二、新建一個DownloadHandler類，它繼承於IHttpHandler接口，能夠用來自定義HTTP 處理程序同步處理HTTP的請求。

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.Diagnostics;
using System.IO;

/// <summary>
///DownloadHandler 的摘要說明
///萬廣互聯（www.wang0214.com）
///專業品牌網站建設
/// </summary>
public class DownloadHandler : IHttpHandler
{
    public void ProcessRequest(HttpContext context)
    {
        HttpResponse Response = context.Response;
        HttpRequest Request = context.Request;
        System.IO.Stream iStream = null;
        byte[] buffer = new Byte[10240];
        int length;
        long dataToRead;
        try
        {
            string filename = FileHelper.Decrypt(Request["fn"]); //經過解密獲得文件名
            string filepath = HttpContext.Current.Server.MapPath("~/") + "files/" + filename; //待下載的文件路徑
            iStream = new System.IO.FileStream(filepath, System.IO.FileMode.Open,
            System.IO.FileAccess.Read, System.IO.FileShare.Read);
            Response.Clear();
            dataToRead = iStream.Length;
            long p = 0;
            if (Request.Headers["Range"] != null)
            {
                Response.StatusCode = 206;
                p = long.Parse(Request.Headers["Range"].Replace("bytes=", "").Replace("-", ""));
            }
            if (p != 0)
            {
                Response.AddHeader("Content-Range", "bytes " + p.ToString() + "-" + ((long)(dataToRead - 1)).ToString() + "/" + dataToRead.ToString());
            }
            Response.AddHeader("Content-Length", ((long)(dataToRead - p)).ToString());
            Response.ContentType = "application/octet-stream";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + System.Web.HttpUtility.UrlEncode(System.Text.Encoding.GetEncoding(65001).GetBytes(Path.GetFileName(filename))));
            iStream.Position = p;
            dataToRead = dataToRead - p;
            while (dataToRead > 0)
            {
                if (Response.IsClientConnected)
                {
                    length = iStream.Read(buffer, 0, 10240);
                    Response.OutputStream.Write(buffer, 0, length);
                    Response.Flush();
                    buffer = new Byte[10240];
                    dataToRead = dataToRead - length;
                }
                else
                {
                    dataToRead = -1;
                }
            }
        }
        catch (Exception ex)
        {
            Response.Write("Error : " + ex.Message);
        }
        finally
        {
            if (iStream != null)
            {
                iStream.Close();
            }
            Response.End();
        }
    }
    public bool IsReusable
    {
        get { return true; }
    }
}

三、這裏涉及到一個文件名加解密的問題，是爲了防止文件具體名稱暴露在狀態欄中，因此添加一個FileHelper類，代碼以下：

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
///FileHelper 的摘要說明
/// </summary>
public class FileHelper
{
    public static string Encrypt(string filename)
    {
        byte[] buffer = HttpContext.Current.Request.ContentEncoding.GetBytes(filename);
        return HttpUtility.UrlEncode(Convert.ToBase64String(buffer));
    }
    public static string Decrypt(string encryptfilename)
    {
        byte[] buffer = Convert.FromBase64String(encryptfilename);
        return HttpContext.Current.Request.ContentEncoding.GetString(buffer);
    }
}

四、在Web.config上，添加httpHandlers結點，以下：

<system.web>
      <httpHandlers>
        <add verb="*" path="download.aspx" type="DownloadHandler" />
      </httpHandlers>
</system.web>

五、如今新建一個aspx頁面，對文件進行下載：
Default.aspx代碼以下：
Default.aspx Code

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!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 id="Head1" runat="server">
<title>文件下載</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:HyperLink ID="link" runat="server" Text="文件下載"></asp:HyperLink>
</div>
</form>
</body>
</html>

Default.aspx.cs代碼以下：
Default.aspx.cs Code

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.Diagnostics;

public partial class _Default : System.Web.UI.Page
{   
    //全局變量
    private static object _SyncLockObject = new object();

    protected void Page_Load(object sender, EventArgs e)
    {
        string url = FileHelper.Encrypt("萬廣互聯_深圳網站建設.jpg");
        link.NavigateUrl = "~/download.aspx?fn=" + url;
    }
}

經過以上詳解講解後，還不能領會的把，就下載下面的源代碼吧：

開始下載：點擊下載解壓密碼：www.wang0214.com