http多线程下载

 

using System;
using System.IO;
using System.Net;
using System.Text;
using System.Security;
using System.Threading;
using System.Collections.Specialized;
using System.Diagnostics;
using System.Data;

namespace HttpDownload.DownloadFile
...{
    /**//// <summary>
    /// Download file info
    /// </summary>
    [Serializable()]
    public class DownloadFileInfo
    ...{
        private string _requestURL;
        private string _responseURL;
        private string _fileName;
        private int _totalSize;
        private int _blockLeftSize;

        public string RequestURL
        ...{
            get ...{ return _requestURL; }
        }

        public string ResponseURL
        ...{
            get ...{ return _responseURL; }
        }

        public string FileName
        ...{
            get ...{ return _fileName; }
        }

        public int TotalSize
        ...{
            get ...{ return _totalSize; }
            set ...{ _totalSize = value; }
        }

        public int BlockLeftSize
        ...{
            get ...{ return _blockLeftSize; }
            set ...{ _blockLeftSize = value; }
        }

        public DownloadFileInfo(string requestURL, string responseURL, string fileName, int totalSize, int blockLeftSize)
        ...{
            this._requestURL = requestURL;
            this._responseURL = responseURL;
            this._fileName = fileName;
            this._totalSize = totalSize;
            this._blockLeftSize = blockLeftSize;
        }

        public DownloadFileInfo(string requestURL, string responseURL, string fileName)
            : this(requestURL, responseURL, fileName, 0, 0)
        ...{
        }

        public DownloadFileInfo(string url, string fileName)
            : this(url, url, fileName, 0, 0)
        ...{
        }

        private DownloadFileInfo()
        ...{
        }

        public static DownloadFileInfo CreatFileInfo(DataRow drFileInfo)
        ...{
            DownloadFileInfo newFileInfo = new DownloadFileInfo();
            newFileInfo._requestURL = drFileInfo["RequestURL"].ToString();
            newFileInfo._responseURL = drFileInfo["ResponseURL"].ToString();
            newFileInfo._fileName = drFileInfo["FileName"].ToString();
            newFileInfo._totalSize = Convert.ToInt32(drFileInfo["TotalSize"].ToString());
            newFileInfo._blockLeftSize = Convert.ToInt32(drFileInfo["BlockLeftSize"].ToString());
            return newFileInfo;
        }
    }

    /**//// <summary>
    /// Download event arguments
    /// </summary>
    public class DownLoadEventArgs : System.EventArgs
    ...{
        private DownloadFileInfo _downloadFileInfo;
        private int _position;
        private int _readCount;
        private int _threadNO;

        public DownloadFileInfo DownFileInfo
        ...{
            get ...{ return _downloadFileInfo; }
        }

        public int StartPosition
        ...{
            get ...{ return _position; }
        }

        public int ReadCount
        ...{
            get ...{ return _readCount; }
        }

        public int ThreadNO
        ...{
            get ...{ return _threadNO; }
        }

        public DownLoadEventArgs(DownloadFileInfo DownFileInfo, int nStartPostion, int nReadCount, int nThreadNO)
        ...{
            this._downloadFileInfo = DownFileInfo;
            this._position = nStartPostion;
            this._readCount = nReadCount;
            this._threadNO = nThreadNO;
        }
    }

    /**//// <summary>
    /// class for sub-download threads
    /// </summary>
    public class SubDownloadThread
    ...{
        private int _threadNO;
        private int _position;
        private int _blockSizeLeft;
        private bool _isStopped;
        private Thread thdDownload;
        const int BUFFER_SIZE = 0x10000;//64k buffer size
        private readonly DownloadFileInfo _fileInfo;
        private EventHandler _finished;
        public event EventHandler<DownLoadEventArgs> DataReceived;

        public SubDownloadThread(DownloadFileInfo DownFileInfo, int ThreadNO, int Position, int BlockSizeLeft, EventHandler Finished)
        ...{
            this._fileInfo = DownFileInfo;
            this._threadNO = ThreadNO;
            this._position = Position;
            this._blockSizeLeft = BlockSizeLeft;
            this._finished = Finished;
        }

        /**//// <summary>
        /// Start to create thread to download file
        /// </summary>

        public void StartDownload()
        ...{
            thdDownload = new Thread(new ThreadStart(this.Download));
            thdDownload.Start();
        }

        /**//// <summary>
        /// Stop current download-thread
        /// </summary>
        public void Stop()
        ...{
            _isStopped = true;
            if (thdDownload.ThreadState == System.Threading.ThreadState.Running)
            ...{
                thdDownload.Join(10);
            }
            Debug.WriteLine(string.Format("Thread NO:{0} is stopped!", _threadNO));
        }

        /**//// <summary>
        /// Function for sub-thread
        /// </summary>
        private void Download()
        ...{
            HttpWebResponse hwrp = null;
            try
            ...{
                Debug.WriteLine(string.Format("Thread NO:{0} begins to download!", _threadNO));
                // Creat request by url 
                HttpWebRequest hwrq = (HttpWebRequest)WebRequest.Create(new Uri(this._fileInfo.RequestURL));
                // Go to download position
                hwrq.AddRange(_position);
                // Get response from request
                hwrp = (HttpWebResponse)hwrq.GetResponse();
            }
            catch (Exception e)
            ...{
                Debug.WriteLine(e.Message);
                return;
            }
            // download and write data from 
            Debug.WriteLine(string.Format("Thread NO:{0} call function named DownloadData!", _threadNO));
            DownloadData(hwrp);
            hwrp.Close();//Close response here
        }

        /**//// <summary>
        /// Download data through web request
        /// </summary>
        /// <param name="Response"></param>
        private void DownloadData(WebResponse Response)
        ...{
            byte[] bBuffer = new byte[BUFFER_SIZE];

            Stream sReader = Response.GetResponseStream();
            if (sReader == null) return;
            int nReadCount = 0;

            while (!_isStopped && this._blockSizeLeft > 0)
            ...{
                Debug.WriteLine(string.Format("Thread NO:{0} reads data!", _threadNO));
                // Set read size
                nReadCount = (BUFFER_SIZE > this._blockSizeLeft) ? this._blockSizeLeft : BUFFER_SIZE;//Get current read count

                // Read data
                int nRealReadCount = sReader.Read(bBuffer, 0, nReadCount);
                if (nRealReadCount <= 0) break;
                Debug.WriteLine(string.Format("Thread NO:{0} writes data!", _threadNO));
                // Write data
                using (FileStream sw = new FileStream(this._fileInfo.FileName + DownloadThread.filenameExt, 
                    System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite))
                ...{
                    sw.Position = this._position;
                    sw.Write(bBuffer, 0, nRealReadCount);
                    Debug.WriteLine(string.Format("Thread NO:{0} writes {1} data!", _threadNO, nRealReadCount));
                    sw.Flush();
                    sw.Close();
                }

                Debug.WriteLine(string.Format("Thread NO:{0} send callback info!", _threadNO));

                // Call back
                EventHandler<DownLoadEventArgs> receivedHandler = DataReceived;
                if (receivedHandler != null)
                ...{
                    receivedHandler(this,new DownLoadEventArgs(
                        this._fileInfo, this._position, nRealReadCount, this._threadNO));
                }

                // Set position and block left 
                this._position += nRealReadCount;
                this._blockSizeLeft -= nRealReadCount;
            }

            if (_isStopped)
            ...{
                return;
            }
            Debug.WriteLine(string.Format("Thread NO:{0} sends finish-info!", _threadNO));
            EventHandler finishHandle = _finished;
            if (finishHandle != null)
            ...{
                finishHandle(this,EventArgs.Empty);
            }
        }
    }

    /**//// <summary>
    /// Class for download thread
    /// </summary>
    public class DownloadThread
    ...{
        private DownloadFileInfo _fileInfo;
        private SubDownloadThread[] subThreads;
        private int nThreadFinishedCount;
        private DataRow drFileInfo;
        private DataTable dtThreadInfo;
        public EventHandler<DownLoadEventArgs> DataReceived;
        public event EventHandler Finished;
        public  const string filenameExt = ".bf!";      //未下载完的扩展名

        public DataTable ThreadInfo
        ...{
            get ...{ return dtThreadInfo; }
        }

        /**//// Class's Constructor
        public DownloadThread(string requestURL, string responseURL, string fileName, DataRow newFileInfo, int subThreadNum)
        ...{
            // Create download file info
            _fileInfo = new DownloadFileInfo(requestURL, responseURL, fileName);
            // Create request to get file info
            bool blnMultiDownload = GetFileDownInfo();

            // Create file info datarow
            drFileInfo = newFileInfo;
            InitDataRow();
            // Create subthreads and set these info in threadinfo table
            if (subThreadNum <= 0) subThreadNum = 5;//Defualt value
            //Not support to be multi-thread download or less than 64k
            if (!blnMultiDownload || _fileInfo.TotalSize <= 0x10000) subThreadNum = 1;
            subThreads = new SubDownloadThread[subThreadNum];
            nThreadFinishedCount = 0;
            CreateThreadTable(subThreadNum);
        }

        public DownloadThread(string url, string fileName)
            : this(url, url, fileName, null, 2)
        ...{
        }

        public DownloadThread(DataRow downloadFileInfo, DataTable threadInfos)
        ...{
            // Create download file info
            drFileInfo = downloadFileInfo;
            _fileInfo = new DownloadFileInfo(drFileInfo["RequestURL"].ToString(),
                drFileInfo["ResponseURL"].ToString(),
                drFileInfo["FileName"].ToString(),
                Convert.ToInt32(drFileInfo["TotalSize"].ToString()),
                Convert.ToInt32(drFileInfo["BlockLeftSize"].ToString()));
            // Create sub thread class objects
            dtThreadInfo = threadInfos;
            subThreads = new SubDownloadThread[dtThreadInfo.Rows.Count];
            nThreadFinishedCount = 0;
        }

        /**//// {Class's Constructor}
        /// <summary>
        /// Start to download
        /// </summary>
        public void Start()
        ...{
            StartSubThreads();
        }

        /**//// <summary>
        /// Create table to save thread info 
        /// </summary>
        /// <param name="SubThreadNum"></param>
        private void CreateThreadTable(int SubThreadNum)
        ...{
            int nThunkSize = _fileInfo.TotalSize / SubThreadNum;
            dtThreadInfo = new DataTable("DownloadFileInfo");
            dtThreadInfo.Columns.Add("ThreadNO", typeof(int));
            dtThreadInfo.Columns.Add("Position", typeof(int));
            dtThreadInfo.Columns.Add("BlockLeftSize", typeof(int));

            DataRow drNew;
            int i = 0;
            for (; i < SubThreadNum - 1; i++)
            ...{
                drNew = dtThreadInfo.NewRow();
                drNew["ThreadNO"] = i;
                drNew["Position"] = i * nThunkSize;
                drNew["BlockLeftSize"] = nThunkSize;
                dtThreadInfo.Rows.Add(drNew);
            }

            drNew = dtThreadInfo.NewRow();
            drNew["ThreadNO"] = i;
            drNew["Position"] = i * nThunkSize;
            drNew["BlockLeftSize"] = _fileInfo.TotalSize - i * nThunkSize;
            dtThreadInfo.Rows.Add(drNew);
            dtThreadInfo.AcceptChanges();
        }

        /**//// <summary>
        /// Start sub-threads to download file
        /// </summary>
        private void StartSubThreads()
        ...{
            foreach (DataRow dr in dtThreadInfo.Rows)
            ...{
                int ThreadNO = Convert.ToInt32(dr["ThreadNO"].ToString());
                if (Convert.ToInt32(dr["BlockLeftSize"].ToString()) > 0)
                ...{
                    subThreads[ThreadNO] = new SubDownloadThread(_fileInfo, ThreadNO,
                        Convert.ToInt32(dr["Position"].ToString()),
                        Convert.ToInt32(dr["BlockLeftSize"].ToString()),
                        new EventHandler(this.DownloadFinished));
                    subThreads[ThreadNO].DataReceived += this.DataReceived;
                    subThreads[ThreadNO].StartDownload();
                }
                else
                ...{
                    DownloadFinished(this,EventArgs.Empty);
                }
            }
        }

        /**//// <summary>
        /// Save download file info
        /// </summary>
        private void InitDataRow()
        ...{
            if (drFileInfo != null)
            ...{
                drFileInfo.BeginEdit();
                drFileInfo["RequestURL"] = _fileInfo.RequestURL;
                drFileInfo["ResponseURL"] = _fileInfo.ResponseURL;
                drFileInfo["FileName"] = _fileInfo.FileName;
                drFileInfo["TotalSize"] = _fileInfo.TotalSize;
                drFileInfo["BlockLeftSize"] = _fileInfo.BlockLeftSize;
                drFileInfo["CreatedTime"] = DateTime.Now.ToString("yyyyMMddHHmmss");
                drFileInfo.EndEdit();
                drFileInfo.AcceptChanges();
            }
        }

        /**//// <summary>
        /// Check url to get download file info
        /// </summary>
        /// <returns></returns>
        private bool GetFileDownInfo()
        ...{
            HttpWebRequest hwrq;
            HttpWebResponse hwrp = null;
            try
            ...{
                //Create request
                hwrq = (HttpWebRequest)WebRequest.Create(_fileInfo.RequestURL);
                hwrp = (HttpWebResponse)hwrq.GetResponse();
                //Get file size info
                long L = hwrp.ContentLength;
                L = ((L == -1) || (L > 0x7fffffff)) ? ((long)0x7fffffff) : L;

                _fileInfo.TotalSize = (int)L;
                _fileInfo.BlockLeftSize = _fileInfo.TotalSize;

                //Check whether this url is supported to be multi-threads download
                bool blnMulti = (hwrp.Headers["Accept-Ranges"] != null && hwrp.Headers["Accept-Ranges"] == "bytes");
                hwrp.Close();//Close response here
                return blnMulti;
            }
            catch (Exception e)
            ...{
                throw e;
            }
        }

        /**//// <summary>
        /// Update download thread info
        /// </summary>
        /// <param name="ThreadNO"></param>
        /// <param name="Position"></param>
        /// <param name="DownloadSize"></param>
        public void UpdateDownloadInfo(int ThreadNO, int Position, int DownloadSize)
        ...{
            if (ThreadNO >= dtThreadInfo.Rows.Count)
            ...{
                return;
            }
            DataRow drThreadNO = dtThreadInfo.Rows[ThreadNO];
            drThreadNO["Position"] = Position + DownloadSize;
            drThreadNO["BlockLeftSize"] = Convert.ToInt32(drThreadNO["BlockLeftSize"].ToString())
                - DownloadSize;
            drThreadNO.AcceptChanges();

            drFileInfo["BlockLeftSize"] = Convert.ToInt32(drFileInfo["BlockLeftSize"].ToString()) - DownloadSize;
        }

        /**//// <summary>
        /// Stop download threads
        /// </summary>
        public void Stop()
        ...{
            for (int i = 0; i < subThreads.Length; i++)
            ...{
                subThreads[i].Stop();
            }
        }

        /**//// <summary>
        /// Thread download finished
        /// </summary>
        private void DownloadFinished(object sender,EventArgs e)
        ...{
            // Some download thread finished
            nThreadFinishedCount++;
            if (nThreadFinishedCount == subThreads.Length)
            ...{
                // All download threads finished
                if (drFileInfo != null)
                ...{
                    drFileInfo.Delete();
                    drFileInfo.AcceptChanges();
                }

                File.Move(_fileInfo.FileName + filenameExt, GetNewFilename(_fileInfo.FileName));

                EventHandler handler = Finished;
                if (handler != null)
                ...{
                    handler(this,EventArgs.Empty);
                }
            }
        }
        /**//// <summary>
        /// 得到新名称
        /// </summary>
        /// <returns></returns>
        public static string GetNewFilename(string filename)
        ...{
            if (File.Exists(filename))
            ...{
                string newname = filename;
                int i = 0;
                int lastPoint = filename.LastIndexOf('.');
                do
                ...{
                    i++;
                    if (lastPoint < 1)
                    ...{
                        newname = filename + "(" + i + ")";
                    }
                    else
                    ...{
                        newname = filename.Substring(0, lastPoint) + "(" + i + ")" + filename.Substring(lastPoint);
                    }
                }
                while (File.Exists(newname));
                return newname;
            }
            else
            ...{
                return filename;
            }
        }
    }
}