using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Net;
using System.Threading;
namespace Update
{
class MultiThreadDownLoad
{
#region 變量
private int _threadNum; //線程數量
private long _fileSize; //文件大小
private string _extName; //文件擴展名
private string _fileUrl; //文件地址
private string _fileName; //文件名
private string _savePath; //保存路徑
private short _threadCompleteNum; //線程完成數量
private bool _isComplete; //是否完成
private volatile int _downloadSize; //當前下載大小(實時的)
public Thread[] _thread; //線程數組
private List<string> _tempFiles = new List<string>();
private List<List<int>> readft = new List<List<int>>();//存放每個線程讀取的起始和結束位置
private object locker = new object();
#endregion
#region 屬性
public string FileName
{
get
{
return _fileName;
}
set
{
_fileName = value;
}
}
public long FileSize
{
get
{
return _fileSize;
}
}
public int DownloadSize
{
get
{
return _downloadSize;
}
}
public bool IsComplete
{
get
{
return _isComplete;
}
set
{
_isComplete = value;
}
}
public int ThreadNum
{
get
{
return _threadNum;
}
}
public string SavePath
{
get
{
return _savePath;
}
set
{
_savePath = value;
}
}
#endregion
/// <summary>
/// 構造函數
/// </summary>
/// <param name="threahNum">線程數量</param>
/// <param name="fileUrl">文件Url路徑</param>
/// <param name="savePath">本地保存路徑</param>
public MultiThreadDownLoad(int threahNum, string fileUrl, string savePath)
{
this._threadNum = threahNum;
this._thread = new Thread[threahNum];
this._fileUrl = fileUrl;
this._savePath = savePath;
}
//_serverUrl為http://xxx.xx/xx.dll形式
//_localFile為\\Program File\xx.dll形式 PS:終端路徑
public void Start()
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(_fileUrl);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
_extName = response.ResponseUri.ToString().Substring(response.ResponseUri.ToString().LastIndexOf('.'));//獲取真實擴展名
_fileSize = response.ContentLength;
int singelNum = (int)(_fileSize / _threadNum); //平均分配
int remainder = (int)(_fileSize % _threadNum); //獲取剩余的
request.Abort();
response.Close();
for (int i = 0; i < _threadNum; i++)
{
List<int> range = new List<int>();
range.Add(i * singelNum);
if (remainder != 0 && (_threadNum - 1) == i) //剩余的交給最後一個線程
range.Add(i * singelNum + singelNum + remainder - 1);
else
range.Add(i * singelNum + singelNum - 1);
readft.Add(range);
_thread[i] = new Thread(new ThreadStart(Download));
_thread[i].Name = i.ToString();
_thread[i].Start();
}
}
private void Download()
{
Stream httpFileStream = null, localFileStram = null;
try
{
string tmpFileBlock = String.Format(@"{0}\{1}_{2}.dat",_savePath,FileName ,Thread.CurrentThread.Name);
_tempFiles.Add(tmpFileBlock);
HttpWebRequest httprequest = (HttpWebRequest)HttpWebRequest.Create(_fileUrl);
httprequest.AddRange(readft[Convert.ToInt32(Thread.CurrentThread.Name)][0], readft[Convert.ToInt32(Thread.CurrentThread.Name)][1]);
HttpWebResponse httpresponse = (HttpWebResponse)httprequest.GetResponse();
httpFileStream = httpresponse.GetResponseStream();
localFileStram = new FileStream(tmpFileBlock, FileMode.Create);
byte[] by = new byte[1024];
int getByteSize = httpFileStream.Read(by, 0, 1024); //Read方法將返回讀入by變量中的總字節數
while (getByteSize > 0)
{
Thread.Sleep(20);
lock (locker) _downloadSize += getByteSize;
localFileStram.Write(by, 0, getByteSize);
getByteSize = httpFileStream.Read(by, 0, 1024);
}
lock (locker)
_threadCompleteNum++;
}
catch (Exception ex)
{
throw new Exception(ex.Message.ToString());
}
finally
{
if (httpFileStream != null) httpFileStream.Close();
if (localFileStram != null) localFileStram.Close();
}
if (_threadCompleteNum == _threadNum)
{
Complete();
_isComplete = true;
}
}
/// <summary>
/// 下載完成後合並文件塊
/// </summary>
private void Complete()
{
Stream mergeFile=null;
BinaryWriter AddWriter=null;
try
{
mergeFile = new FileStream(String.Format(@"{0}\{1}", _savePath, FileName), FileMode.Create);
AddWriter = new BinaryWriter(mergeFile);
foreach (string file in _tempFiles)
{
using (FileStream fs = new FileStream(file, FileMode.Open))
{
BinaryReader TempReader = new BinaryReader(fs);
AddWriter.Write(TempReader.ReadBytes((int)fs.Length));
TempReader.Close();
}
File.Delete(file);
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
AddWriter.Close();
mergeFile.Close();
}
}
}
}
摘自 #Define
