网页登陆，网页采集基础类

昨天在博客园上看到了关于秒杀的文章，通过模拟网页数据传送的方式达到更快的网页访问操作！有些时候模拟网页访问还是蛮有用的，比如自动登陆，网页采集等等。下面的几个方法就是我用到的几个类，虽然方法比较少，但基本的要求还是能满足的。

    public static class HtmlHelper
    {
        /// <summary>
        /// 获得基础流
        /// </summary>
        /// <param name="uri">网址</param>
        /// <param name="cc">cookie容器，可以为NULL</param>
        /// <returns></returns>
        public static Stream GetBaseStream(string uri, CookieContainer cc)
        {
            try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);   //用指定Uri创建一个request
                if (cc != null)
                {
                    request.CookieContainer = cc;
                }
                //浏览器欺骗
                request.ContentType = "application/x-www-form-urlencoded";
                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 5.1; en-US) AppleWebKit/533.2 (KHTML, like Gecko) Chrome/5.0.342.9 Safari/533.2 ChromePlus/1.3.9.0";

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();      //根据创建的request得到响应response
                Stream responseStream = response.GetResponseStream();  //创建一个流来获得响应体
                return responseStream;
            }
            catch (Exception ex)
            {
                MessageBox.Show(@"操作失败：" + ex.Message);
                return null;
            }
        }

        /// <summary>
        /// 获得网页
        /// </summary>
        /// <param name="uri">网址</param>
        /// <param name="postDate"></param>
        /// <param name="cc">cookie容器，可以为null</param>
        /// <param name="encoding">网页编码</param>
        /// <returns></returns>
        public static string GetHtmlString(string uri, string postDate, CookieContainer cc, Encoding encoding)
        {
            try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
                request.ContentType = "application/x-www-form-urlencoded";
                request.AllowAutoRedirect = true;
                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 5.1; en-US) AppleWebKit/533.2 (KHTML, like Gecko) Chrome/5.0.342.9 Safari/533.2 ChromePlus/1.3.9.0";
                request.CookieContainer = cc;     //设置request产生cookie的容器
                if (postDate != null)
                {
                    request.Method = "Post";
                    byte[] byterequest = Encoding.UTF8.GetBytes(postDate);
                    request.ContentLength = byterequest.Length;
                    using (Stream stream = request.GetRequestStream())
                    {
                        stream.Write(byterequest, 0, byterequest.Length);
                    }

                }

                using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
                {
                    using (Stream responsestream = response.GetResponseStream())
                    {
                        StreamReader sr = new StreamReader(responsestream, encoding);
                        string html = sr.ReadToEnd();
                        return html;
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(@"发生错误:" + ex.Message);
                return null;
            }
        }

        /// <summary>
        /// 从字符串中返回匹配多个的集合值（网页抽取特定部分有效）
        /// </summary>
        /// <param name="start">开始html tag</param>
        /// <param name="end">结束html tag</param>
        /// <param name="html">html</param>
        /// <returns></returns>
        public static List<string> GetStrings(string start, string end, string html)
        {
            List<string> list = new List<string>();
            try
            {
                string pattern = string.Format("{0}(?<g>(.|[\r\n])+?){1}", start, end);//匹配URL的模式,并分组    //理解这个正则
                MatchCollection mc = Regex.Matches(html, pattern);//满足pattern的匹配集合
                if (mc.Count != 0)
                {
                    foreach (Match match in mc)
                    {
                        GroupCollection gc = match.Groups;
                        list.Add(gc["g"].Value);
                    }
                }
            }
            catch
            { }
            return list;
        }

        /// <summary>
        /// 中文url编码
        /// </summary>
        /// <param name="buffer"></param>
        /// <returns></returns>
        public static string UrlEncode(string buffer)
        {
            byte[] bty = Encoding.Default.GetBytes(buffer);
            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < bty.Length; i++)
            {
                builder.Append("%");
                builder.Append(bty[i].ToString("x2"));
            }
            return builder.ToString();
        }
    }