类代码：
using System.Threading;
using System.IO;
using System.Web;
using
System.ComponentModel;
using System.Net;
using
System.Text.RegularExpressions;
using System.Collections;
/// <summary>
/// 多线程下载类
/// </summary>
public class MultiDownload
{
#region 变量
private int
_threadNum; //线程数量
private long _fileSize;
//文件大小
private string _extName; //文件扩展名
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();
_extName =
response.ResponseUri.ToString().Substring(response.ResponseUri.ToString().LastIndexOf('.'));//获取真实扩展名
_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);
//_thread[i] = new Thread(new
ThreadStart(Download(range[0], range[1])));
from = range[0];
to = range[1];//下载指定位置的数据
_thread[i] = new Thread(new
ThreadStart(Download));
_thread[i].Name =
"jhxz_{0}".Replace("{0}", Convert.ToString(i + 1));
_thread[i].Start();
}
}
public int from,
to;
#region 下载网页
private void Download()
{
Stream httpFileStream = null, localFileStram =
null;
try
{
//string
tmpFileBlock = @"{0}\{1}_{2}.dat".Formats(_savePath, _fileName,
Thread.CurrentThread.Name);
string tmpFileBlock = @_savePath
+ "\\" + _fileName + "_" + Thread.CurrentThread.Name +
".dat";
_tempFiles.Add(tmpFileBlock);
HttpWebRequest httprequest =
(HttpWebRequest)WebRequest.Create(_fileUrl);
httprequest.AddRange(from, to);
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;
}
}
#endregion
/// <summary>
/// 下载完成后合并文件块
///
</summary>
private void Complete()
{
//Stream mergeFile = new FileStream(@"{0}\{1}{2}".Formats(_savePath, _fileName,
_extName), FileMode.Create);
Stream mergeFile = new
FileStream(@_savePath + "\\" + _fileName + _extName,
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();
}
}
前台使用 MultiDownload dow = new MultiDownload(10, "http://www.xxxxxxx.com%22,application.startuppath/);
dow.FileName = "boyuan";