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1、模拟用户登录；保存登录状态；抓取数据技术点：模拟用户登录；保存登录状态；抓取数据程序非常简单： / / visit the target url / / /this is for keeping cookies and sessions /this is the data need post inside form /html page public static string PostAndGetHTML(string targetURL,CookieContainer cc, Hashtable param) /prepare the submit data string formData
2、 = ; foreach (DictionaryEntry de in param) formData += de.Key.ToString() + = + de.Value.ToString()+&; if(formData.Length0) formData = formData.Substring(0, formData.Length - 1); /remove last & ASCIIEncoding encoding = new ASCIIEncoding(); byte data = encoding.GetBytes(formData); HttpWebRequest reque
3、st = (HttpWebRequest)WebRequest.Create(targetURL); request.Method = POST; /postrequest.ContentType = application/x-www-form-urlencoded; request.ContentLength = data.Length; request.UserAgent = Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; SV1; .NET CLR 2.0.1124); Stream newStream = request.GetR
4、equestStream(); newStream.Write(data, 0, data.Length); newStream.Close(); request.CookieContainer = cc; HttpWebResponse response = (HttpWebResponse)request.GetResponse(); cc.Add(response.Cookies); Stream stream = response.GetResponseStream(); string result = new StreamReader(stream, System.Text.Enco
5、ding.Default).ReadToEnd(); return result; 这一个是调用的例子：先登录，在查询。 实际中这个逻辑可能有很多步骤 private void button2_Click(object sender, EventArgs e) CookieContainer cc = new CookieContainer();/this is for keep the Session and Cookie Hashtable param = new Hashtable();/this is for keep post data. string urlLogin = http
6、:/demo.server/login.asp; /do find the elementId that needed. check the source of login page can get this information param.Add(User, xxx); param.Add(Password, xxxx); string result = PostAndGetHTML(urlLogin, cc, param); /check result, whether login success /if login success, goto the target url, and
7、input some value. string url2 = http:/demo.server/query.asp?id=1;/ need change. special logic param.Clear(); /param.Add(SearchAreaId,JobId) result = PostAndGetHTML(url2, cc, new Hashtable(); /ConvertToDT the html or do something others 这是一个简单的抓取网页数据的函数（针对Table内的，直接转化成DataTable） private DataTable Con
8、vertToDT(DataTable dt, string tableHTML) int lastTD = tableHTML.ToLower().LastIndexOf(); int firstRow = tableHTML.ToLower().IndexOf(tr) + 3;/after tr int index = tableHTML.ToLower().IndexOf(tr, firstRow) + 3;/after tr while (index lastTD) DataRow dr = dt.NewRow(); for (int i = 0; i dt.Columns.Count;
9、 i+) string value = ; int startTD = tableHTML.ToLower().IndexOf(td, index) + 3;/after td int endTD = tableHTML.ToLower().IndexOf(, startTD); if (endTD 0) break; string tdStr = tableHTML.Substring(startTD, endTD - startTD); /remove and others tdStr = tdStr.Replace( , ).Replace(t, ).Replace(r, ); string v = tdStr.Split(); for (int j = 0; j v.Length; j+) j+; if (vj.Trim() != ) value = vj.Trim(); break; / dri = value; index = endTD; dt.Rows.Add(dr); return dt; 注：对于有验证码登录系统的无效。（如果该系统的验证码放到cookie中存储的例外，这个容易破解）转自：http:/
