好了，还是由于工作需要 要登录一个网站并且模拟点击下载某些东西
原理就是先对一个地址（地址是用户名和密码输入框所在的form的action对应的页面）进行POST提交用户名和密码（不考虑验证码，当然验证码也可以破解），用一个CookieContainer保持Response的cookie，保证了每次请求使用同一个已经登录的session。
本类部分代码来源于网上，功能有待完善，目前只实现了登录和登录后访问“后台”页面。
代码：
public class LogingHelper { public static CookieContainer theCC = new CookieContainer(); /// <summary> /// 登录方法(无验证码) /// </summary> /// <param name="url">POST请求的地址 /// <param name="paramList">参数列表 例如 name=zhangsan&pass=lisi /// <param name="referer">来源地址 /// <returns></returns> public static string Login(String url, String paramList, string referer) { HttpWebResponse res = null; HttpWebRequest req = null; string strResult = ""; try { req = (HttpWebRequest)WebRequest.Create(url); //配置请求header req.Headers.Add(HttpRequestHeader.AcceptCharset, "GBK,utf-8;q=0.7,*;q=0.3"); req.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate,sdch"); req.Headers.Add(HttpRequestHeader.AcceptLanguage, "zh-CN,zh;q=0.8"); req.Accept = "application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5"; req.KeepAlive = true; req.Referer = referer; req.Headers.Add(HttpRequestHeader.CacheControl, "max-age=0"); req.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.5 Safari/534.7"; req.Method = "POST"; req.ContentType = "application/x-www-form-urlencoded"; req.AllowAutoRedirect = true; //设置cookieContainer用来接收cookie req.CookieContainer = theCC; StringBuilder UrlEncoded = new StringBuilder(); //对参数进行encode Char[] reserved = { '?', '=', '&' }; byte[] SomeBytes = null; if (paramList != null) { int i = 0, j; while (i < paramList.Length) { j = paramList.IndexOfAny(reserved, i); if (j == -1) { UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length - i))); break; } UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j - i))); UrlEncoded.Append(paramList.Substring(j, 1)); i = j + 1; } SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString()); req.ContentLength = SomeBytes.Length; Stream newStream = req.GetRequestStream(); newStream.Write(SomeBytes, 0, SomeBytes.Length); newStream.Close(); } else { req.ContentLength = 0; } //返回请求 res = (HttpWebResponse)req.GetResponse(); Encoding encode = System.Text.Encoding.GetEncoding("utf-8"); Stream responseStream = null; if (res.ContentEncoding.ToLower() == "gzip") { responseStream = new System.IO.Compression.GZipStream(res.GetResponseStream(), System.IO.Compression.CompressionMode.Decompress); } else if (res.ContentEncoding.ToLower() == "deflate") { responseStream = new System.IO.Compression.DeflateStream(res.GetResponseStream(), System.IO.Compression.CompressionMode.Decompress); } else { responseStream = res.GetResponseStream(); } StreamReader sr = new StreamReader(responseStream, encode); strResult = sr.ReadToEnd(); } catch (Exception e) { //writeLog } finally { res.Close(); } return strResult; } /// <summary> 获取页面HTML /// /// <param name="url"> /// <param name="paramList"> /// <returns></returns> public static string getPage(String url, string referer) { HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); string strResult = string.Empty; req.Headers["If-None-Match"] = "36d0ed736e88c71:d9f"; req.Referer = referer; req.CookieContainer = theCC; HttpWebResponse res = (HttpWebResponse)req.GetResponse(); StreamReader sr = null; try { sr = new StreamReader(res.GetResponseStream(), Encoding.UTF8); strResult = sr.ReadToEnd(); } catch (System.Exception ex) { //writeLog } finally { sr.Close(); } return strResult; } /// <summary> /// 模仿异步请求POST的方法 /// </summary> /// <param name="url"> /// <param name="referer"> /// <param name="methed"> /// <param name="paramList"> /// <returns></returns> public static string VisitPage(string url, string referer, string paramList) { HttpWebResponse response = null; string strResult = string.Empty; try { HttpWebRequest request = HttpWebRequest.Create(url) as HttpWebRequest; request.Method = "POST"; request.KeepAlive = true; request.Referer = referer; request.Headers.Add(HttpRequestHeader.AcceptCharset, "GBK,utf-8;q=0.7,*;q=0.3"); request.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate,sdch"); request.Headers.Add(HttpRequestHeader.AcceptLanguage, "zh-CN,zh;q=0.8"); request.Accept = "application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5"; request.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.5 Safari/534.7"; request.ContentType = "application/x-www-form-urlencoded"; request.CookieContainer = theCC; request.Headers.Add("X-Requested-With", "XMLHttpRequest"); StringBuilder UrlEncoded = new StringBuilder(); //对参数进行encode Char[] reserved = { '?', '=', '&' }; byte[] SomeBytes = null; if (paramList != null) { int i = 0, j; while (i < paramList.Length) { j = paramList.IndexOfAny(reserved, i); if (j == -1) { UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length - i))); break; } UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j - i))); UrlEncoded.Append(paramList.Substring(j, 1)); i = j + 1; } SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString()); request.ContentLength = SomeBytes.Length; Stream newStream = request.GetRequestStream(); newStream.Write(SomeBytes, 0, SomeBytes.Length); newStream.Close(); } response = (HttpWebResponse)request.GetResponse(); Encoding encode = System.Text.Encoding.GetEncoding("utf-8"); Stream responseStream = null; if (response.ContentEncoding.ToLower() == "gzip") { responseStream = new System.IO.Compression.GZipStream(response.GetResponseStream(), System.IO.Compression.CompressionMode.Decompress); } else if (response.ContentEncoding.ToLower() == "deflate") { responseStream = new System.IO.Compression.DeflateStream(response.GetResponseStream(), System.IO.Compression.CompressionMode.Decompress); } else { responseStream = response.GetResponseStream(); } StreamReader sr = new StreamReader(responseStream, encode); strResult = sr.ReadToEnd(); } catch { //dosomething } finally { response.Close(); } return strResult; } }
调用示例：
static void Main(string[] args) { string userName = "lxnanhr"; string userPwd = "lxnanhr"; string content = LogingHelper.Login("http://www.aa.com/index.php?c=login&m=chklogin", "uname=xxx&pass=xxx", "http://www.aa.com/index.php?c=login"); Console.WriteLine(content); Console.WriteLine(LogingHelper.getPage("http://www.aa.com/index.php?c=preview&m=view&resume_id=1179406405&keyword=", "http://www.aa.com/index.php?c=search&m=supersearch#")); Console.ReadLine(); }