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  • Asp.net(c#)实现多线程断点续传

    以前一直错误的认为在ASP.NET中无法通过编程方式实现多线程断点续传,今天终于获得了这样一个解决方案,让我明白要学习的东西还很多。
    此解决方案基于其它解决方案及相关资料,根据我自己的理解改进.如有错漏,请尽管指出;如有其它更好的解决方案,请推荐一下,感谢先。

    System.IO.Stream iStream = null;

                
    // Buffer to read 10K bytes in chunk:
                byte[] buffer = new Byte[10240];

                
    // Length of the file:
                int length;

                
    // Total bytes to read:
                long dataToRead;

                
    // Identify the file to download including its path.
                string filepath  = @"E:\software\SQL Server 2000 Personal Edition.ISO";

                
    // Identify the file name.
                string  filename  = System.IO.Path.GetFileName(filepath);

                
    try
                
    {
                    
    // Open the file.
                    iStream = new System.IO.FileStream(filepath, System.IO.FileMode.Open, 
                        System.IO.FileAccess.Read,System.IO.FileShare.Read);
                    Response.Clear();

                    
    // Total bytes to read:
                    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(Request.ContentEncoding.GetBytes(filename)));

                    iStream.Position 
    = p;
                    dataToRead 
    = dataToRead - p;
                    
    // Read the bytes.
                    while (dataToRead > 0)
                    
    {
                        
    // Verify that the client is connected.
                        if (Response.IsClientConnected) 
                        
    {
                            
    // Read the data in buffer.
                            length = iStream.Read(buffer, 010240);

                            
    // Write the data to the current output stream.
                            Response.OutputStream.Write(buffer, 0, length);

                            
    // Flush the data to the HTML output.
                            Response.Flush();

                            buffer
    = new Byte[10240];
                            dataToRead 
    = dataToRead - length;
                        }

                        
    else
                        
    {
                            
    //prevent infinite loop if user disconnects
                            dataToRead = -1;
                        }

                    }

                }

                
    catch (Exception ex) 
                
    {
                    
    // Trap the error, if any.
                    Response.Write("Error : " + ex.Message);
                }

                
    finally
                
    {
                    
    if (iStream != null
                    
    {
                        
    //Close the file.
                        iStream.Close();
                    }
                       Response.End();
                }


    本解决方案所参考的资料链接列表(在此对作者表示感谢):
    http://blog.csdn.net/playyuer/archive/2004/08/02/58430.aspx
    http://www.httpsniffer.com/http/1416.htm
    http://support.microsoft.com/default.aspx?scid=kb;en-us;812406&Product=aspnet

    更新:
            此解决方案已根据playyuer 提出的问题作了更新,另外在输出前调用了Response.Clear();方法。

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  • 原文地址:https://www.cnblogs.com/Leo_wl/p/1805078.html
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