c# 多线程下载 示例代码

using System;using System.Collections.Generic;using System.Text;using System.Threading;using System.Net;using System.IO;namespace 多线程下载{ public class HttpLoadFile { private bool isFinish=false; /// <summary> /// 全局下载完成标志 /// </summary> public bool IsFinish { get { return isFinish; } } private bool[] isFinishList; //每个线程结束标志 /// <summary> /// 结束标志 /// </summary> public bool[] IsFinishList { get { return isFinishList; } } private string[] taskFileList; /// <summary> /// 每个线程接收的拆分文件 提供给各线程使用 helper /// </summary> public string[] TaskFileList { get { return taskFileList; } } private int[] taskStartList; /// <summary> /// 每个线程接收拆分后文件的起始位置 提供给各线程使用 helper类 /// </summary> public int[] TaskStartList { get { return taskStartList; } } private int[] taskSizeList; /// <summary> /// /每个线程接收拆分后文件的大小 提供给各线程使用 helper /// </summary> public int[] TaskSizeList { get { return taskSizeList; } } private string sourceUrl; //接受文件的URL /// <summary> /// 下载源链接 /// </summary> public string SourceUrl { get { return sourceUrl; } set { sourceUrl = value; } } private int taskCount; //进程数 /// <summary> /// 开启下载线程数 /// </summary> public int TaskCount { get { return taskCount; } set { taskCount = value; } } private string saveFilePath; /// <summary> /// 存储文件位置 /// </summary> public string SaveFilePath { get { return saveFilePath; } set { saveFilePath = value; } } private string errMsg; /// <summary> /// 出错信息 /// </summary> public string ErrMsg { get { return errMsg; } } private HttpWebRequest request; private bool isMerge; //文件合并标志 private long fileSize = 0; //源文件大小 /// <summary> /// 错误通知 /// </summary> public event EventHandler<HttpLoadFileEventArgs> Error; /// <summary> /// 全部下载完成通知 /// </summary> public event EventHandler<HttpLoadFileEventArgs> AllFinished; /// <summary> /// 子线程完成通知 /// </summary> public event EventHandler<HttpLoadFileEventArgs> SubFinished; /// <summary> /// 构造函数 提供下载链接，使用几线程下载，存储文置 /// </summary> /// <param name="sourceUrl">下载链接</param> /// <param name="taskCount">开启几线程下载</param> /// <param name="saveFilePath">存储文置</param> public HttpLoadFile(string sourceUrl, int taskCount, string saveFilePath) { this.sourceUrl = sourceUrl; this.taskCount = taskCount; this.saveFilePath = saveFilePath; } public bool DownLoad() { try { //初始化连接 InitConnection(); //开始每个线程下载 DownLoadTask(); //完成通知外界定制类 isFinish = true; AllFinishNotify(); return true; } catch (Exception ex) { //失败通知外界定制类 isFinish = false; AllErrorNotify(); return false; } } /// <summary> /// 全局任务出错触发事件通知方法 /// </summary> protected void AllErrorNotify() { if (Error != null) { HttpLoadFileEventArgs args = new HttpLoadFileEventArgs(); args.TaskCount = taskCount; args.SourceUrl = sourceUrl; args.SaveFilePath = saveFilePath; args.IsFinish = false; args.ErrMsg = errMsg; Error(this, args); } } /// <summary> /// 全部任务完成触发事件通知方法 /// </summary> protected void AllFinishNotify() { if (AllFinished != null) { HttpLoadFileEventArgs args = new HttpLoadFileEventArgs(); args.TaskCount = taskCount; args.SourceUrl = sourceUrl; args.SaveFilePath = saveFilePath; args.IsFinish = true; args.ErrMsg = "No Error!"; args.TaskIndex = taskCount; AllFinished(this, args); } } /// <summary> /// 子任务线程出错触发事件通知方法 /// <param name="args"></param> protected void SubErrorNotify(HttpLoadFileEventArgs args) { if (Error != null) { Error(this, args); } } /// <summary> /// 子任务线程完成触发事件通知方法 /// </summary> /// <param name="args"></param> protected void SubFinishNotity(HttpLoadFileEventArgs args) { if (SubFinished != null) { SubFinished(this, args); } } protected void DownLoadTask() { try { //定义线程数组，启动接收线程 Thread[] threadList = new Thread[this.taskCount]; LoadFileHelper[] helpers = new LoadFileHelper[taskCount]; for (int j = 0; j < taskCount; j ) { helpers[j] = new LoadFileHelper(this, j); //当各线程下载完或下载出错，请通知主类更新 下载结束标志或出错信息 helpers[j].Error =new EventHandler<HttpLoadFileEventArgs>(HttpLoadFile_Error); helpers[j].Finished = new EventHandler<HttpLoadFileEventArgs>(HttpLoadFile_Finished); threadList[j] = new Thread(new ThreadStart(helpers[j].LoadTaskFile)); threadList[j].Start(); } //启动合并各线程接收的文件线程 Thread mergeThread = new Thread(new ThreadStart(MergeFile)); mergeThread.Start(); } catch (Exception ex) { throw new Exception("开始多线程任务下载出错：" ex.Message); } } protected void HttpLoadFile_Error(object sender, HttpLoadFileEventArgs e) { errMsg = e.ErrMsg; SubErrorNotify(e); } protected void HttpLoadFile_Finished(object sender, HttpLoadFileEventArgs e) { isFinishList[e.TaskIndex] = e.IsFinish; SubFinishNotity(e); } ~HttpLoadFile()//析构方法 { GC.SuppressFinalize(this); } /// <summary> /// 试连接并获取文件大小 /// </summary> protected void InitConnection() { try { request = (HttpWebRequest)HttpWebRequest.Create(sourceUrl); fileSize = request.GetResponse().ContentLength; //取得目标文件的长度 request.Abort(); //根据线程数初始化数组 isFinishList = new bool[taskCount]; taskFileList = new string[taskCount]; taskStartList = new int[taskCount]; taskSizeList = new int[taskCount]; //计算每个任务的要下载的文件大小及起点位置 InitTaskList(); } catch (HttpListenerException ex) { throw new Exception("无法连接目标地址,原因" ex.Message); } } /// <summary> /// 拆分计算出每个任务接收文件的大小和接收起点位置 /// </summary> protected void InitTaskList() { //计算每个线程应该接收文件的大小 int averageTaskFileSize = (int)fileSize / taskCount;//平均分配 int lasTaskFileSize = averageTaskFileSize (int)fileSize % taskCount;//剩余部分由最后一个线程完成 //为数组赋值 for (int i = 0; i < taskCount; i ) { isFinishList[i] = false;//每个线程状态的初始值为假 taskFileList[i] = i.ToString() ".dat";//每个线程接收文件的临时文件名 if (i < taskCount - 1) { taskStartList[i] = averageTaskFileSize * i;//每个线程接收文件的起始点 taskSizeList[i] = averageTaskFileSize - 1;//每个线程接收文件的长度 } else { taskStartList[i] = averageTaskFileSize * i; taskSizeList[i] = lasTaskFileSize - 1; } } } /// <summary> /// 合并各任务下载的文件，并存于指定位置 /// </summary> /// <returns></returns> protected void MergeFile() { //开始合并 FileStream fs = null; FileStream fstemp = null; try { while (true)//等待 { isMerge = true; for (int i = 0; i < taskCount; i ) { if (isFinishList[i] == false)//有未结束线程，等待 { isMerge = false; Thread.Sleep(100); break; } } if (isMerge == true)//所有线程均已结束，停止等待， { break; } } int readfile; byte[] bytes = new byte[512]; fs = new FileStream(saveFilePath, System.IO.FileMode.Create); for (int k = 0; k < taskCount; k ) { fstemp = new FileStream(taskFileList[k], System.IO.FileMode.Open); while (true) { readfile = fstemp.Read(bytes, 0, 512); if (readfile > 0) { fs.Write(bytes, 0, readfile); } else { break; } } fstemp.Close(); } fs.Close(); } catch (IOException ex) { fstemp.Close(); fs.Close(); throw new Exception("合并任务文件出错，原因：" ex.Message); } } } /// <summary> /// HttpLoadFile 事件参数类 /// </summary> public class HttpLoadFileEventArgs : EventArgs { private int taskCount; //进程数 /// <summary> /// 开启下载线程数 /// </summary> public int TaskCount { get { return taskCount; } set { taskCount = value; } } private string sourceUrl; /// <summary> /// 下载源链接 /// </summary> public string SourceUrl { get { return sourceUrl; } set { sourceUrl = value; } } private string saveFilePath; /// <summary> /// 存储文件位置 /// </summary> public string SaveFilePath { get { return saveFilePath; } set { saveFilePath = value; } } private string errMsg; /// <summary> /// 错误信息 /// </summary> public string ErrMsg { get { return errMsg; } set { errMsg = value; } } private bool isFinish; /// <summary> /// 完成标志 /// </summary> public bool IsFinish { get { return isFinish; } set { isFinish = value; } } private int taskIndex; /// <summary> /// 当前第几个线程 /// </summary> public int TaskIndex { get { return taskIndex; } set { taskIndex = value; } } public HttpLoadFileEventArgs() { } } /// <summary> /// 用于Thread线程调用的类（MSDN建设这样，线程委托的方法如果带参数可以通过类把其参数封装成属性或变量） /// </summary> class LoadFileHelper { private HttpWebRequest request; private HttpLoadFile httpLoadFile; private int taskIndex; private string errMsg; public event EventHandler<HttpLoadFileEventArgs> Error; public event EventHandler<HttpLoadFileEventArgs> Finished; public LoadFileHelper(HttpLoadFile httpLoadFile, int taskIndex) { this.httpLoadFile = httpLoadFile; this.taskIndex = taskIndex; } /// <summary> /// 根据任务编号开启每个任务下载 /// </summary> /// <param name="taskIndex"></param> public void LoadTaskFile() { FileStream fs; System.IO.Stream ns; byte[] nbytes;//接收缓冲区 int nreadsize;//接收字节数 ns = null; nbytes = new byte[512]; nreadsize = 0; //("线程" taskIndex.ToString() "开始接收");-----------------------------------------关注每个任务线程开始 fs = new FileStream(httpLoadFile.TaskFileList[taskIndex], System.IO.FileMode.Create); try { request = (HttpWebRequest)WebRequest.Create(httpLoadFile.SourceUrl); //接收的起始位置及接收的长度 request.AddRange(httpLoadFile.TaskStartList[taskIndex], httpLoadFile.TaskStartList[taskIndex] httpLoadFile.TaskSizeList[taskIndex]); ns = request.GetResponse().GetResponseStream();//获得接收流 nreadsize = ns.Read(nbytes, 0, 512); while (nreadsize > 0) { fs.Write(nbytes, 0, nreadsize); nreadsize = ns.Read(nbytes, 0, 512); //("线程" taskIndex.ToString() "正在接收");----------------------------------关注每个任务线程进行 } fs.Close(); ns.Close(); //("进程" taskIndex.ToString() "接收完毕!");-----------------------------------------关注每个任务线程结束 //httpLoadFile.IsFinishList[taskIndex] = true; //触发事件通知HttpDownLoad下载完毕，并更新对应IsFinishList[taskIndex]结束标识的状态 FinishNotify(); } catch (HttpListenerException ex) { errMsg = "第[" taskIndex.ToString() "]条任务线程发生错误，原因：" ex.Message; ns.Close(); fs.Close(); //触发事件通知其中某个线程下载任务出错 ErrorNotify(); } } protected void FinishNotify() { if(Finished!=null) { HttpLoadFileEventArgs args = new HttpLoadFileEventArgs(); args.TaskIndex = this.taskIndex; args.IsFinish=true; args.ErrMsg= "No Error!"; args.SourceUrl = httpLoadFile.SourceUrl; args.SaveFilePath = httpLoadFile.SaveFilePath; args.TaskCount = httpLoadFile.TaskCount; Finished(this, args); } } protected void ErrorNotify() { if (Error != null) { HttpLoadFileEventArgs args = new HttpLoadFileEventArgs(); args.TaskIndex = this.taskIndex; args.IsFinish = false; args.ErrMsg = errMsg; args.SourceUrl = httpLoadFile.SourceUrl; args.SaveFilePath = httpLoadFile.SaveFilePath; args.TaskCount = httpLoadFile.TaskCount; Error(this, args); } } } }