.net几种文件下载的方法

.Net文件下载方式。。。。

　　之前在写上传文件、下载文件的时候，发现Response对象里面有好几种下载文件的方式，之后自己亲自实践了这几种方法，记录下以便以后复习。。。

WriteFile文件下载

      public void getFile(string path, string fileName)
         {
             FileInfo fileInfo = new FileInfo(path);
             Response.Clear();
             Response.ClearContent();
             Response.ClearHeaders();
             Response.ContentType = "application/octet-stream";//设置输出流的 HTTP MIME 类型
             //Content-Disposition 为二进制格式提供已知MIME类型的“文件下载”对话框或建议动态内容的文件名的机会
             Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));// URL 字符串进行编码，防止出现乱码
             //回应消息体的长度，以 字节 （8位为一字节）为单位
             Response.AddHeader("Content-Length", fileInfo.Length + "");
             //文件传输编码  二进制
             Response.AddHeader("Content-Transfer-Encoding", "binary");
             //指定文件的内容作为文件块直接写入 HTTP 响应输出流
             Response.WriteFile(fileInfo.FullName);
             Response.Flush();
             Response.End();
         }

BinaryWrite流文件下载

     public void getFile1(string path, string fileName)
         {
             FileStream stream = File.Open(path, FileMode.Open); // FileStream stream = new FileStream(path,FileMode.Open);
             byte[] buffer = new byte[(int)stream.Length];
             stream.Read(buffer, , buffer.Length);
             stream.Close();//文件流需要手动关闭，或者用using自动关闭
             Response.Clear();
             Response.ContentType = "application/octet-stream";
             //通知浏览器下载
             Response.AddHeader("Content-Disposition", "attachment;filename=" + System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
             //将二进制字符串写入 HTTP 输出流,已经是二进制了，就不需要 Response.AddHeader("Content-Transfer-Encoding", "binary");
             Response.BinaryWrite(buffer);
             Response.Flush();
             Response.End();
         }

大文件分块下載

  public void getFile2(string path, string fileName)
         {
             FileInfo fileInfo = new FileInfo(path);
             if (fileInfo.Exists)
             {
                 const long standardSize = *;//定义一个静态常量，每次读取200K，缓解服务器压力（大文件更好下载）
                 FileStream stream = File.OpenRead(path);
                 byte[] buffer = new byte[standardSize];
                 long dataFielSize = stream.Length;//下载文件总大小
                 Response.Clear();
                 Response.ContentType = "application/octet-stream";
                 Response.AddHeader("Content-Disposition", "attachment;filename=" + System.Web.HttpUtility.UrlEncode(fileName));
                 Response.AddHeader("Content-Length", fileInfo.Length.ToString());
                 Response.AddHeader("Content-Transfer-Encoding", "binary");
                 Response.ContentEncoding = System.Text.Encoding.Default;
                 if (dataFielSize >  && Response.IsClientConnected)
                 {
                     int readLengtn = stream.Read(buffer, , (int)standardSize);
                     Response.OutputStream.Write(buffer, , readLengtn);
                     Response.Flush();
                     dataFielSize = dataFielSize - readLengtn;
                 }
                 stream.Close();
                 Response.Close();
             }
         }

TransmitFile文件下载

    public void getFile4(string path, string fileName)
         {
             Response.Clear();
             Response.ContentType = "application/octet-stream";
             Response.AddHeader("Content-Disposition", "attachment;filename=" + System.Web.HttpUtility.UrlEncode(fileName));
             Response.TransmitFile(path);
         }

JSWindow打开文件

    public void getFile3(string path)
         {
             Response.Write("<script>window.open('" + path + "')</script>");//文件打开可以下载，图片打开就是在线预览
         }

方法调用函数如下：

   protected void btnn_Click(object sender, EventArgs e)
         {
             Button btn = (Button)sender;
             //var aa = Request.MapPath("../Pages/uploadfiles");//Request对象获取绝对路径
             var filesArr = Directory.GetFiles(Server.MapPath("../Pages/uploadfiles"));//Server对象获取绝对路径
             var tempArr = filesArr[].Split('\\');
             var jsdownLoadUrl = "../Pages/uploadfiles/" + tempArr[tempArr.Length - ];
             var fileName = "图片下载";
             switch (btn.ID)
             {
                 case "btn1":
                     getFile(filesArr[], fileName);
                     break;
                 case "btn2":
                     getFile1(filesArr[], fileName);
                     break;
                 case "btn3":
                     getFile2(filesArr[], fileName);
                     break;
                 case "btn4":
                     getFile3(jsdownLoadUrl);
                     break;
                 case "btn5":
                     getFile4(filesArr[], fileName);
                     break;
                 default:
                     break;
             }         }