Net/C#: 实现支持断点续传多线程下载2

.Net/C#: 实现支持断点续传多线程下载的 Http Web 客户端工具类 (C# DIY HttpWebClient)

/* .Net/C#: 实现支持断点续传多线程下载的 Http Web 客户端工具类 (C# DIY HttpWebClient) * Reflector 了一下 System.Net.WebClient ,重载或增加了若干: * DownLoad、Upload 相关方法! * DownLoad 相关改动较大! * 增加了 DataReceive、ExceptionOccurrs 事件! * 了解服务器端与客户端交互的 HTTP 协议参阅: * 使文件下载的自定义连接支持 FlashGet 的断点续传多线程链接下载! JSP/Servlet 实现! * http://blog.csdn.net/playyuer/archive/2004/08/02/58430.aspx * 使文件下载的自定义连接支持 FlashGet 的断点续传多线程链接下载! C#/ASP.Net 实现! * http://blog.csdn.net/playyuer/archive/2004/08/02/58281.aspx */ namespace Microshaoft.Utils { using System; using System.IO; using System.Net; using System.Text; using System.Security; using System.Threading; using System.Collections.Specialized; /// /// 记录下载的字节位置 /// public class DownLoadState { private string _FileName; private string _AttachmentName; private int _Position; private string _RequestURL; private string _ResponseURL; private int _Length; private byte[] _Data; public string FileName { get { return _FileName; } } public int Position { get { return _Position; } } public int Length { get { return _Length; } } public string AttachmentName { get { return _AttachmentName; } } public string RequestURL { get { return _RequestURL; } } public string ResponseURL { get { return _ResponseURL; } } public byte[] Data { get { return _Data; } } internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, byte[] Data) { this._FileName = FileName; this._RequestURL = RequestURL; this._ResponseURL = ResponseURL; this._AttachmentName = AttachmentName; this._Position = Position; this._Data = Data; this._Length = Length; } internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, ThreadCallbackHandler tch) { this._RequestURL = RequestURL; this._ResponseURL = ResponseURL; this._FileName = FileName; this._AttachmentName = AttachmentName; this._Position = Position; this._Length = Length; this._ThreadCallback = tch; } internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length) { this._RequestURL = RequestURL; this._ResponseURL = ResponseURL; this._FileName = FileName; this._AttachmentName = AttachmentName; this._Position = Position; this._Length = Length; } private ThreadCallbackHandler _ThreadCallback; // internal void StartDownloadFileChunk() { if (this._ThreadCallback != null) { this._ThreadCallback(this._RequestURL, this._FileName, this._Position, this._Length); } } } //委托代理线程的所执行的方法签名一致 public delegate void ThreadCallbackHandler(string S, string s, int I, int i); //异常处理动作 public enum ExceptionActions { Throw, CancelAll, Ignore, Retry } /// /// 包含 Exception 事件数据的类 /// public class ExceptionEventArgs : System.EventArgs { private System.Exception _Exception; private ExceptionActions _ExceptionAction; private DownLoadState _DownloadState; public DownLoadState DownloadState { get { return _DownloadState; } } public Exception Exception { get { return _Exception; } } public ExceptionActions ExceptionAction { get { return _ExceptionAction; } set { _ExceptionAction = value; } } internal ExceptionEventArgs(System.Exception e, DownLoadState DownloadState) { this._Exception = e; this._DownloadState = DownloadState; } } /// /// 包含 DownLoad 事件数据的类 /// public class DownLoadEventArgs : System.EventArgs { private DownLoadState _DownloadState; public DownLoadState DownloadState { get { return _DownloadState; } } public DownLoadEventArgs(DownLoadState DownloadState) { this._DownloadState = DownloadState; } } /// /// 支持断点续传多线程下载的类 /// public class HttpWebClient { private static object _SyncLockObject = new object(); public delegate void DataReceiveEventHandler(HttpWebClient Sender, DownLoadEventArgs e); public event DataReceiveEventHandler DataReceive; //接收字节数据事件 public delegate void ExceptionEventHandler(HttpWebClient Sender, ExceptionEventArgs e); public event ExceptionEventHandler ExceptionOccurrs; //发生异常事件 private int _FileLength; //下载文件的总大小 public int FileLength { get { return _FileLength; } } /// /// 分块下载文件 /// /// URL 地址 /// 保存到本地的路径文件名 /// 块数,线程数 public void DownloadFile(string Address, string FileName, int ChunksCount) { int p = 0; // position int s = 0; // chunk size string a = null; HttpWebRequest hwrq; HttpWebResponse hwrp = null; try { hwrq = (HttpWebRequest) WebRequest.Create(this.GetUri(Address)); hwrp = (HttpWebResponse) hwrq.GetResponse(); long L = hwrp.ContentLength; hwrq.Credentials = this.m_credentials; L = ((L == -1) || (L > 0x7fffffff)) ? ((long) 0x7fffffff) : L; //Int32.MaxValue 该常数的值为 2,147,483,647; 即十六进制的 0x7FFFFFFF int l = (int) L; this._FileLength = l; // 在本地预定空间(竟然在多线程下不用先预定空间) // FileStream sw = new FileStream(FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite); // sw.Write(new byte[l], 0, l); // sw.Close(); // sw = null; bool b = (hwrp.Headers["Accept-Ranges"] != null & hwrp.Headers["Accept-Ranges"] == "bytes"); a = hwrp.Headers["Content-Disp