如何在上传时实现断点续传

Question

如题，是上传的时候

Answer 1

        #region 文件上传
       
       /// <summary>
       /// 上传文件（自动分割）
       /// </summary>
       /// <param name="filePath">待上传的文件全路径名称(@"E:\FTP\ftproot\20070228DQCK.zip")</param>
       /// <param name="hostURL">服务器的地址</param>
       /// <param name="byteCount">分割的字节大小</param>        
       /// <param name="userID">主机用户ID</param>
       /// <param name="cruuent">当前字节指针</param>
       /// <returns>成功返回"";失败则返回错误信息</returns>
        public string UpLoadFile(string filePath, string hostURL, int byteCount,string userID,long cruuent)
        {
            string tmpURL = hostURL;
            byteCount = byteCount * 1024;
            //http://localhost:8080/fism/app?service=fileupload&beanId=com.cfcc.fism.service.upload.CollFileSaveServiceImpl&action=upload&filename=AI1215900000020051130411.zip&userid=test&npos=333
            //action=length            System.Net.WebClient WebClientObj = new System.Net.WebClient();
            FileStream fStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
            BinaryReader bReader = new BinaryReader(fStream);
            long length = fStream.Length;           
            string sMsg = "版式上传成功";
            string fileName = filePath.Substring(filePath.LastIndexOf('\\') + 1);           
            try
            {                #region 续传处理
                byte[] data;
                if (cruuent > 0)
                {
                    fStream.Seek(cruuent, SeekOrigin.Current);
                }
                #endregion                  #region 分割文件上传
                for (; cruuent <= length; cruuent = cruuent + byteCount)
                { 
                    if (cruuent + byteCount > length)
                    {
                        data = new byte[Convert.ToInt64((length - cruuent))];
                        bReader.Read(data, 0, Convert.ToInt32((length - cruuent)));
                    }
                    else
                    {
                        data = new byte[byteCount];
                        bReader.Read(data, 0, byteCount);
                    }                    try
                    { 
                        LOG.Debug(data);                         //***
                        hostURL = tmpURL + "&action=upload" + "&filename=" + fileName + "&userid=" + userID + "&npos=" + cruuent.ToString();
                        byte[] byRemoteInfo = WebClientObj.UploadData(hostURL, "POST", data);
                        string sRemoteInfo = System.Text.Encoding.Default.GetString(byRemoteInfo);                      //  获取返回信息
                        if (sRemoteInfo.Trim() != "")
                        {
                            sMsg =  sRemoteInfo;
                            break;                        }
                    }
                    catch (Exception ex)
                    {
                        sMsg =  ex.ToString();
                        break;
                    }
                #endregion                }
            }
            catch (Exception ex)
            {
                sMsg = sMsg + ex.ToString(); 
            }
            try
            { 
                bReader.Close();
                fStream.Close();
            }
            catch (Exception exMsg)
            {
                sMsg =  exMsg.ToString();
            }            GC.Collect();
            return sMsg;
        } 
        #endregion
   #region 获取文件大小
       /// <summary>
       /// 获取远程服务器文件字节大小
       /// </summary>
       /// <param name="filePath">待上传的文件全路径名称</param>
       /// <param name="hostURL">服务器的地址</param>
       /// <param name="userID">主机用户ID</param>
       /// <returns>远程文件大小</returns>
        public long GetRemoteFileLength(string filePath, string hostURL, string userID)
       {
           long length = 0; 
           System.Net.WebClient WebClientObj = new System.Net.WebClient();  
           
           string fileName = filePath.Substring(filePath.LastIndexOf('\\') + 1);
           
           hostURL = hostURL +"&action=length" + "&filename=" + fileName + "&userid=" + userID + "&npos=0" ;
           
           byte[] data = new byte[0];
           byte[] byRemoteInfo = WebClientObj.UploadData(hostURL , "POST", data);
           string sRemoteInfo = System.Text.Encoding.Default.GetString(byRemoteInfo);//主系统没有作异常处理
           try
           {
               length = Convert.ToInt64(sRemoteInfo);
           }
           catch (Exception exx)
           {
               LOG.Error("FileLib类GetRemoteFileLength()中length = Convert.ToInt64(sRemoteInfo)语句异常：" + exx.Message);//我们强制处理异常
               length = 0;
           }
           GC.Collect();           return length;       }

Answer 2

你在进行续传时，先从服务器获取 文件的大小，然后 把这个大小作为 一个 偏移量，从这个位置继续读取本地文件进行上传，可以达到续传的目的，上面的代码是 我用 .Net 和 Servlet 进行续传时的代码，可以作为参考服务器端需要写的方法有两个：（1）获取服务器上的文件大小，Response，（2）续写文件流

Answer 3

我写的是公用类啊，并没有限定是 CS 还是 Web 方式的上传，只要调用就可以了啊Web上传的话，用 FileInput 或者其他的脚本来选择 本地文件，然后执行上传代码就可以了