同步和异步方式获取网页源代码！

1.先来个异步的方式，获取网页源码：

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

namespace TestSolution.BLL
{
    public class MyHttpPage
    {
        public static ManualResetEvent allDone = new ManualResetEvent(false);
        const int BUFFER_SIZE = 1024;
        const int DefaultTimeout = 2 * 60 * 1000; // 2 minutes timeout

        // Abort the request if the timer fires.
        private static void TimeoutCallback(object state, bool timedOut)
        {
            if (timedOut)
            {
                HttpWebRequest request = state as HttpWebRequest;
                if (request != null)
                {
                    request.Abort();
                }
            }
        }

        public static string GetPage(string url)
        {
            try
            {
                // Create a HttpWebrequest object to the desired URL. 
                HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create(url);

                //myHttpWebRequest.UserAgent = "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727; Alexa Toolbar)";
                
                /**
                  * If you are behind a firewall and you do not have your browser proxy setup
                  * you need to use the following proxy creation code.

                    // Create a proxy object.
                    WebProxy myProxy = new WebProxy();

                    // Associate a new Uri object to the _wProxy object, using the proxy address
                    // selected by the user.
                    myProxy.Address = new Uri("http://myproxy");
       
        
                    // Finally, initialize the Web request object proxy property with the _wProxy
                    // object.
                    myHttpWebRequest.Proxy=myProxy;
                  ***/

                // Create an instance of the RequestState and assign the previous myHttpWebRequest
                // object to its request field.  
                RequestState myRequestState = new RequestState();
                myRequestState.request = myHttpWebRequest;


                // Start the asynchronous request.
                IAsyncResult result =
                  (IAsyncResult)myHttpWebRequest.BeginGetResponse(new AsyncCallback(RespCallback), myRequestState);

                // this line implements the timeout, if there is a timeout, the callback fires and the request becomes aborted
                ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), myHttpWebRequest, DefaultTimeout, true);

                // The response came in the allowed time. The work processing will happen in the 
                // callback function.
                allDone.WaitOne();
                allDone.Reset();

                //返回数据
                return myRequestState.requestData.ToString();

                // Release the HttpWebResponse resource.                
                //myRequestState.response.Close();
            }
            catch (WebException e)
            {
                Console.WriteLine("\nMain Exception raised!");
                Console.WriteLine("\nMessage:{0}", e.Message);
                Console.WriteLine("\nStatus:{0}", e.Status);
                Console.WriteLine("Press any key to continue.");
                return "";
            }
            catch (Exception e)
            {
                Console.WriteLine("\nMain Exception raised!");
                Console.WriteLine("Source :{0} ", e.Source);
                Console.WriteLine("Message :{0} ", e.Message);
                Console.WriteLine("Press any key to continue.");
                Console.Read();
                return "";
            }

        }


        private static void RespCallback(IAsyncResult asynchronousResult)
        {
            try
            {
                // State of request is asynchronous.
                RequestState myRequestState = (RequestState)asynchronousResult.AsyncState;
                HttpWebRequest myHttpWebRequest = myRequestState.request;
                myRequestState.response = (HttpWebResponse)myHttpWebRequest.EndGetResponse(asynchronousResult);

                // Read the response into a Stream object.
                Stream responseStream = myRequestState.response.GetResponseStream();
                myRequestState.streamResponse = responseStream;

                // Begin the Reading of the contents of the HTML page and print it to the console.
                IAsyncResult asynchronousInputRead = responseStream.BeginRead(myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState);
                return;
            }
            catch (WebException e)
            {
                Console.WriteLine("\nRespCallback Exception raised!");
                Console.WriteLine("\nMessage:{0}", e.Message);
                Console.WriteLine("\nStatus:{0}", e.Status);
            }
            allDone.Set();
        }
        private static void ReadCallBack(IAsyncResult asyncResult)
        {
            try
            {

                RequestState myRequestState = (RequestState)asyncResult.AsyncState;
                Stream responseStream = myRequestState.streamResponse;
                int read = responseStream.EndRead(asyncResult);

                //获取编码类型
                string CharacterSet = myRequestState.response.CharacterSet.ToLower();
                string ContentType = myRequestState.response.ContentType;
                string encodeout = "gb2312";//默认编码,获取文档使用的编码方式
                //if (CharacterSet == "utf-8" || CharacterSet == "iso-8859-1" || ContentType.IndexOf("utf-8") > -1)
                if (CharacterSet == "utf-8" || ContentType.IndexOf("utf-8") > -1)
                {
                    encodeout = "utf-8";//utf-8 方式保存
                    //this.outString = "ContentEncoding=" + response.ContentEncoding + "\r\n CharacterSet=" + response.CharacterSet + "\r\n ContentType=" + response.ContentType;
                }

                string patternEncode = @"(?<=<\s*meta[^>]+charset\s*=\s*)utf-8";
                Regex regEncode = new Regex(patternEncode, RegexOptions.IgnoreCase);
                Match match = regEncode.Match(Encoding.ASCII.GetString(myRequestState.BufferRead, 0, read));
                if (match.Success)
                {
                    encodeout = "utf-8";//utf-8 方式保存
                }


                // Read the HTML page and then print it to the console.
                if (read > 0)
                {
                    //以正确的编码方式输出
                    //System.Text.Encoding.GetEncoding(encodeout)
                    //myRequestState.requestData.Append(Encoding.ASCII.GetString(myRequestState.BufferRead, 0, read));
                    myRequestState.requestData.Append(Encoding.GetEncoding(encodeout).GetString(myRequestState.BufferRead, 0, read));
                    IAsyncResult asynchronousResult = responseStream.BeginRead(myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState);
                    return;
                }
                else
                {
                    Console.WriteLine("\nThe contents of the Html page are : ");
                    if (myRequestState.requestData.Length > 1)
                    {
                        //返回HTML数据
                        string stringContent;
                        stringContent = myRequestState.requestData.ToString();
                        Console.WriteLine(stringContent);
                    }
                    Console.WriteLine("Press any key to continue.");
                    Console.ReadLine();

                    responseStream.Close();
                }

            }
            catch (WebException e)
            {
                Console.WriteLine("\nReadCallBack Exception raised!");
                Console.WriteLine("\nMessage:{0}", e.Message);
                Console.WriteLine("\nStatus:{0}", e.Status);
            }
            allDone.Set();

        }
    }

    public class RequestState
    {
        // This class stores the State of the request.
        const int BUFFER_SIZE = 1024;
        public StringBuilder requestData;
        public byte[] BufferRead;
        public HttpWebRequest request;
        public HttpWebResponse response;
        public Stream streamResponse;
        public RequestState()
        {
            BufferRead = new byte[BUFFER_SIZE];
            requestData = new StringBuilder("");
            request = null;
            streamResponse = null;
        }
    }



}

2.再来个同步的方式获取源码：

/***************************************************************************************************
 * Filename:            GetPageHTML.cs
 * Module:              获取URL的源代码，保存到本地
 * Copyright:           2008 杰世科技 版权所有
 * Author:              周林郁
 * Created Date:        2008-10-20
 * Last Modified Data:  
 * Description:         
***************************************************************************************************/
using System;
using System.Collections.Generic;
//using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using System.Threading;

namespace MonitorService
{
    public class GetPageHTML
    {
        // 日志操作类
        WriteLog wl = new WriteLog();
        /// <summary>
        /// 静态生成页面的方法
        /// </summary>
        /// <param name="strPageUrl">生成源</param>
        /// <param name="strFileName">生成到</param>
        public string GetPageCode(string strPageUrl, string strOutFilePath)
        {
            string PageHtml = "";
            //获得aspx的静态html
            try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(strPageUrl);
                //Set the 'Timeout' property in Milliseconds.微秒
                request.Timeout = 180000;//设置3分钟超时,1秒=1000微秒

                // Set some reasonable limits on resources used by this request
                //request.MaximumAutomaticRedirections = 4;
                //request.MaximumResponseHeadersLength = 4;
                // Set credentials to use for this request.
                //request.Credentials = CredentialCache.DefaultCredentials;

                //HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                //判断是否有错误页面，参考：http://blog.joycode.com/ghj/archive/2008/03/12/114957.aspx
                HttpWebResponse response;
                try
                {
                    response = (HttpWebResponse)request.GetResponse();
                }
                catch (WebException ex)
                {
                    response = (HttpWebResponse)ex.Response;
                }

                #region HttpStatusCode 枚举值参考
                /*** HttpStatusCode *************************************************/
                //Continue = 100,
                //SwitchingProtocols = 101,
                //OK = 200,
                //Created = 201,
                //Accepted = 202,
                //NonAuthoritativeInformation = 203,
                //NoContent = 204,
                //ResetContent = 205,
                //PartialContent = 206,
                //MultipleChoices = 300,
                //Ambiguous = 300,
                //MovedPermanently = 301,
                //Moved = 301,
                //Found = 302,
                //Redirect = 302,
                //SeeOther = 303,
                //RedirectMethod = 303,
                //NotModified = 304,
                //UseProxy = 305,
                //Unused = 306,
                //TemporaryRedirect = 307,
                //RedirectKeepVerb = 307,
                //BadRequest = 400,
                //Unauthorized = 401,
                //PaymentRequired = 402,
                //Forbidden = 403,
                //NotFound = 404,
                //MethodNotAllowed = 405,
                //NotAcceptable = 406,
                //ProxyAuthenticationRequired = 407,
                //RequestTimeout = 408,
                //Conflict = 409,
                //Gone = 410,
                //LengthRequired = 411,
                //PreconditionFailed = 412,
                //RequestEntityTooLarge = 413,
                //RequestUriTooLong = 414,
                //UnsupportedMediaType = 415,
                //RequestedRangeNotSatisfiable = 416,
                //ExpectationFailed = 417,
                //InternalServerError = 500,
                //NotImplemented = 501,
                //BadGateway = 502,
                //ServiceUnavailable = 503,
                //GatewayTimeout = 504,
                //HttpVersionNotSupported = 505,
                /*** HttpStatusCode *************************************************/
                //switch (response.StatusCode)
                //{
                //    case HttpStatusCode.OK:
                //        receiveStream = response.GetResponseStream();                        
                //        break;
                //    case HttpStatusCode.Moved:
                //        string s = response.StatusDescription;
                //        //receiveStream = response.GetResponseStream();
                //        break;
                //    case HttpStatusCode.Redirect:
                //        break;
                //    default:
                //        break;
                //}
                #endregion

                //如果文档出错，直接返回
                if (response.StatusCode != HttpStatusCode.OK)
                {
                    response.Close();
                    return "";
                }

                //Get the stream associated with the response.
                //Stream receiveStream = response.GetResponseStream();

                #region 开始读取内容
                // Pipes the stream to a higher level stream reader with the required encoding format.
                //获取编码方式
                string CharacterSet = response.CharacterSet.ToLower();
                string encodeout = "gb2312";//默认编码,获取文档使用的编码方式

                if (CharacterSet == "utf-8" || CharacterSet == "iso-8859-1" || response.ContentType.IndexOf("utf-8") > -1)
                {
                    encodeout = "utf-8";//utf-8 方式保存
                    //this.outString = "ContentEncoding=" + response.ContentEncoding + "\r\n CharacterSet=" + response.CharacterSet + "\r\n ContentType=" + response.ContentType;
                }

                //Encoding encode = System.Text.Encoding.Default;//encode=DBCSCodePageEncoding
                //System.Text.Encoding.GetEncoding(encodeout)
                Stream receiveStream = response.GetResponseStream();
                StreamReader readStream = new StreamReader(receiveStream, System.Text.Encoding.GetEncoding(encodeout));//原来是:System.Text.Encoding.UTF8
                
                PageHtml = readStream.ReadToEnd().ToString();

                //wl.WriteLogMsg("GetPageHTML = " + PageHtml + "\r\n");

                if (strOutFilePath != "" && PageHtml !="" )
                {
                    // 保存
                    PageHtml = PageHtml.Replace("<BR>", "\r\n");
                    string _saveFilePath = System.AppDomain.CurrentDomain.BaseDirectory + strOutFilePath;
                    WriteTextFile(_saveFilePath, PageHtml);
                }
                #endregion

                //判断文档下载是否完成,文档是否正确，readStream.EndOfStream ,response.StatusCode
                //PageHtml.IndexOf("</html>") > -1 || PageHtml.IndexOf("</HTML>") > -1

                #region 释放资源
                 

                //释放所有资源
                readStream.Close();
                readStream.Dispose();
                receiveStream.Close();
                receiveStream.Dispose();
                response.Close();
                #endregion

                return PageHtml;

            }
            catch
            {
                //this.noteMessage = "出错了，请检查网络是否连通;";
                return PageHtml;
            }
        }


        /// <summary> CutX 截取一段文本,包括首尾字符串（包括首尾字符串）
        /// '**函数功能:截取一段文本包括首尾字符串（包括首尾字符串）
        /// '**函数参数:返回截取的文本段
        /// '           s       --要截取的源代码
        /// '           strhead --截取的起始标志
        /// '           strbot  --截取的结束标志
        /// </summary> 
        public string CutX(string s, string strHead, string strBot)
        {

            int iBegin = s.IndexOf(strHead);
            int iEnd = s.IndexOf(strBot, iBegin + 1);
            if (iBegin > 0 && iEnd > 0 && iEnd > iBegin)
            {
                return s.Substring(iBegin, iEnd - iBegin + strBot.Length);
            }
            else
            {
                return "";
            }
        }

        /// <summary> Cut截取一段文本,不包括首尾字符串
        /// '**函数功能:截取一段文本不包括首尾字符串
        /// '**函数参数:返回截取的文本段
        /// '           s       --要截取的源代码
        /// '           strhead --截取的起始标志
        /// '           strbot  --截取的结束标志
        /// </summary> 
        public string Cut(string s, string strHead, string strBot)
        {

            int iBegin = s.IndexOf(strHead) + strHead.Length;
            int iEnd = s.IndexOf(strBot, iBegin + 1);
            if (iBegin > 0 && iEnd > 0 && iEnd > iBegin)
            {
                return s.Substring(iBegin, iEnd - iBegin);
            }
            else
            {
                return "";
            }

        }

        /// <summary> FilterHTML(string strHTML),过滤所有HTML代码
        /// 输入HTML代码，返回过滤后的内容
        /// </summary> 
        public string FilterHTML(string strHTML)
        {
            string TempHtml = strHTML;
            //TempHtml= System.Text.RegularExpressions.Regex.Replace(strHTML, @"<[^>]*>", "");
            TempHtml = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<[^>]+>", "");
            return TempHtml;
        }
        /// <summary> FilterScript(string strHTML),过滤所有脚本代码
        /// 输入HTML代码，返回过滤后的内容
        /// 过滤：<script,<iframe,<NOSCRIPT,<object,<--注析的内容
        /// </summary> 
        public string FilterScript(string strHTML)
        {
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<(s|S)(c|C)(r|R)(i|I)(p|P)(t|T).+?\/(s|S)(c|C)(r|R)(i|I)(p|P)(t|T)>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<SCRIPT([^>])*>(\\w|\\W)*</SCRIPT([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<NOSCRIPT([^>])*>(\\w|\\W)*</NOSCRIPT([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<script([^>])*>(\\w|\\W)*</script([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<noscript([^>])*>(\\w|\\W)*</noscript([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<object([^>])*>(\\w|\\W)*</object([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<(i|I)(f|F)(r|R)(a|A)(m|M)(e|E).+?\/(i|I)(f|F)(r|R)(a|A)(m|M)(e|E)>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<iframe([^>])*>+?\</iframe([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<iframe([^>])*>(\\w|\\W)*</iframe([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<noiframe([^>])*>(\\w|\\W)*</noiframe([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<IFRAME([^>])*>+?\</IFRAME([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<IFRAME([^>])*>(\\w|\\W)*</IFRAME([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<NOIFRAME([^>])*>(\\w|\\W)*</NOIFRAME([^>])*>", "");
            strHTML = System.Text.RegularExpressions.Regex.Replace(strHTML, @"<!-([^>])*>(\\w|\\W)*--([^>])*>", "");
            return strHTML;
        }

        #region WriteTextFile 写入文本文件
        /// <summary>
        /// 将数据写入到文本文件
        /// </summary>
        /// <param name="strFilePath">写入到的位置</param>
        /// <param name="strData">要写入的数据</param>
        /// <returns>如果成功写入，返回True</returns>
        public bool WriteTextFile(string strFilePath, string strData)
        {
            try
            {
                System.IO.StreamWriter sw = new System.IO.StreamWriter(strFilePath, false, System.Text.Encoding.Default);
                sw.Write(strData);
                sw.Close();
                return true;
            }
            catch (Exception e)
            {
                throw (e);
            }
        }
        #endregion
    }
}