多线程下载文件代码,CSharp代码库,德仔网

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【CSharp】多线程下载文件
作者:Gordon / 发布于2015/1/26/ 424

	using System;
	using System.Collections.Generic;
	using System.Linq;
	using System.Text;
	using System.IO;
	using System.Threading;
	using System.Net;

	namespace WfpApp
	{
	 public class MultiDownload
	 {
	 #region 变量

	 private int _threadNum; //线程数量
	 private long _fileSize; //文件大小
	 private string _fileUrl; //文件地址
	 private string _fileName; //文件名
	 private string _savePath; //保存路径
	 private short _threadCompleteNum; //线程完成数量
	 private bool _isComplete; //是否完成
	 private volatile int _downloadSize; //当前下载大小(实时的)
	 private Thread[] _thread; //线程数组
	 private List<string> _tempFiles = new List<string>();
	 private object locker = new object();

	 #endregion
	 #region 属性
	 /// <summary>
	 /// 文件名
	 /// </summary>
	 public string FileName
	 {
	 get
	 {
	 return _fileName;
	 }
	 set
	 {
	 _fileName = value;
	 }
	 }
	 /// <summary>
	 /// 文件大小
	 /// </summary>
	 public long FileSize
	 {
	 get
	 {
	 return _fileSize;
	 }
	 }
	 /// <summary>
	 /// 当前下载大小(实时的)
	 /// </summary>
	 public int DownloadSize
	 {
	 get
	 {
	 return _downloadSize;
	 }
	 }
	 /// <summary>
	 /// 是否完成
	 /// </summary>
	 public bool IsComplete
	 {
	 get
	 {
	 return _isComplete;
	 }
	 }
	 /// <summary>
	 /// 线程数量
	 /// </summary>
	 public int ThreadNum
	 {
	 get
	 {
	 return _threadNum;
	 }
	 }
	 /// <summary>
	 /// 保存路径
	 /// </summary>
	 public string SavePath
	 {
	 get
	 {
	 return _savePath;
	 }
	 set
	 {
	 _savePath = value;
	 }
	 }

	 #endregion

	 /// <summary>
	 /// 构造函数
	 /// </summary>
	 /// <param name="threahNum">线程数量</param>
	 /// <param name="fileUrl">文件Url路径</param>
	 /// <param name="savePath">本地保存路径</param>
	 public MultiDownload(int threahNum, string fileUrl, string savePath)
	 {
	 this._threadNum = threahNum;
	 this._thread = new Thread[threahNum];
	 this._fileUrl = fileUrl;
	 this._savePath = savePath;
	 }

	 public void Start()
	 {
	 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(_fileUrl);
	 HttpWebResponse response = (HttpWebResponse)request.GetResponse();
	 _fileSize = response.ContentLength;
	 int singelNum = (int)(_fileSize / _threadNum); //平均分配
	 int remainder = (int)(_fileSize % _threadNum); //获取剩余的
	 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) //剩余的交给最后一个线程
	 range.Add(i * singelNum + singelNum + remainder - 1);
	 else
	 range.Add(i * singelNum + singelNum - 1);
	 //下载指定位置的数据
	 int[] ran = new int[] { range[0], range[1] };
	 _thread[i] = new Thread(new ParameterizedThreadStart(Download));
	 _thread[i].Name = System.IO.Path.GetFileNameWithoutExtension(_fileUrl) + "_{0}".Replace("{0}", Convert.ToString(i + 1));
	 _thread[i].Start(ran);
	 }
	 }

	

	 private void Download(object obj)
	 {
	 Stream httpFileStream = null, localFileStram = null;
	 try
	 {
	 int[] ran = obj as int[];
	 string tmpFileBlock = System.IO.Path.GetTempPath() + Thread.CurrentThread.Name + ".tmp";
	 _tempFiles.Add(tmpFileBlock);
	 HttpWebRequest httprequest = (HttpWebRequest)WebRequest.Create(_fileUrl);
	 httprequest.AddRange(ran[0], ran[1]);
	 HttpWebResponse httpresponse = (HttpWebResponse)httprequest.GetResponse();
	 httpFileStream = httpresponse.GetResponseStream();
	 localFileStram = new FileStream(tmpFileBlock, FileMode.Create);
	 byte[] by = new byte[5000];
	 int getByteSize = httpFileStream.Read(by, 0, (int)by.Length); //Read方法将返回读入by变量中的总字节数
	 while (getByteSize > 0)
	 {
	 Thread.Sleep(20);
	 lock (locker) _downloadSize += getByteSize;
	 localFileStram.Write(by, 0, getByteSize);
	 getByteSize = httpFileStream.Read(by, 0, (int)by.Length);
	 }
	 lock (locker) _threadCompleteNum++;
	 }
	 catch (Exception ex)
	 {
	 throw new Exception(ex.Message.ToString());
	 }
	 finally
	 {
	 if (httpFileStream != null) httpFileStream.Dispose();
	 if (localFileStram != null) localFileStram.Dispose();
	 }
	 if (_threadCompleteNum == _threadNum)
	 {
	 Complete();
	 _isComplete = true;
	 }
	 }

	 /// <summary>
	 /// 下载完成后合并文件块
	 /// </summary>
	 private void Complete()
	 {
	 Stream mergeFile = new FileStream(@_savePath, FileMode.Create);
	 BinaryWriter 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);
	 }
	 AddWriter.Close();
	 }
	 }
	}

	
	调用：
	string httpUrl = @"http://172.28.98.96/fdimsservice/2.rar";
	string saveUrl = System.Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "//" + System.IO.Path.GetFileName(httpUrl);
	int threadNumber = 5;

	MultiDownload md = new MultiDownload(threadNumber, httpUrl, saveUrl);
	md.Start();
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