本文实例讲述了C#使用正则表达式抓取网站信息的方法。分享给大家供大家参考，具体如下：
这里以抓取京东商城商品详情为例。
1、创建JdRobber.cs程序类
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public class JdRobber{ /// <summary> /// 判断是否京东链接 /// </summary> /// <param name="param"></param> /// <returns></returns> public bool ValidationUrl(string url) { bool result = false; if (!String.IsNullOrEmpty(url)) { Regex regex = new Regex(@"^http://item.jd.com/\d+.html$"); Match match = regex.Match(url); if (match.Success) { result = true; } } return result; } /// <summary> /// 抓取京东信息 /// </summary> /// <param name="param"></param> /// <returns></returns> public void GetInfo(string url) { if (ValidationUrl(url)) { string htmlStr = WebHandler.GetHtmlStr(url, "Default"); if (!String.IsNullOrEmpty(htmlStr)) { string pattern = ""; //正则表达式 string sourceWebID = ""; //商品关键ID string title = ""; //标题 decimal price = 0; //价格 string picName = ""; //图片 //提取商品关键ID pattern = @"http://item.jd.com/(?<Object>\d+).html"; sourceWebID = WebHandler.GetRegexText(url, pattern); //提取标题 pattern = @"<div.*id=\""name\"".*>[\s\S]*<h1>(?<Object>.*?)</h1>"; title = WebHandler.GetRegexText(htmlStr, pattern); //提取图片 int begin = htmlStr.IndexOf("<div id=\"spec-n1\""); int end = htmlStr.IndexOf("</div>", begin + 1); if (begin > 0 && end > 0) { string subPicHtml = htmlStr.Substring(begin, end - begin); pattern = @"<img.*src=\""(?<Object>.*?)\"".*/>"; picName = WebHandler.GetRegexText(subPicHtml, pattern); } //提取价格 if (sourceWebID != "") { string priceUrl = @"http://p.3.cn/prices/get?skuid=J_" + sourceWebID + "&type=1"; string priceJson = WebHandler.GetHtmlStr(priceUrl, "Default"); pattern = @"\""p\"":\""(?<Object>\d+(\.\d{1,2})?)\"""; price = WebHandler.GetValidPrice(WebHandler.GetRegexText(priceJson, pattern)); } Console.WriteLine("商品名称：{0}", title); Console.WriteLine("图片：{0}", picName); Console.WriteLine("价格：{0}", price); } } }} |
2、创建WebHandler.cs公共方法类
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/// <summary>/// 公共方法类/// </summary>public class WebHandler{ /// <summary> /// 获取网页的HTML码 /// </summary> /// <param name="url">链接地址</param> /// <param name="encoding">编码类型</param> /// <returns></returns> public static string GetHtmlStr(string url, string encoding) { string htmlStr = ""; try { if (!String.IsNullOrEmpty(url)) { WebRequest request = WebRequest.Create(url); //实例化WebRequest对象 WebResponse response = request.GetResponse(); //创建WebResponse对象 Stream datastream = response.GetResponseStream(); //创建流对象 Encoding ec = Encoding.Default; if (encoding == "UTF8") { ec = Encoding.UTF8; } else if (encoding == "Default") { ec = Encoding.Default; } StreamReader reader = new StreamReader(datastream, ec); htmlStr = reader.ReadToEnd(); //读取数据 reader.Close(); datastream.Close(); response.Close(); } } catch { } return htmlStr; } /// <summary> /// 获取正则表达式中的关键字 /// </summary> /// <param name="input">文本</param> /// <param name="pattern">表达式</param> /// <returns></returns> public static string GetRegexText(string input, string pattern) { string result = ""; if (!String.IsNullOrEmpty(input) && !String.IsNullOrEmpty(pattern)) { Regex regex = new Regex(pattern, RegexOptions.IgnoreCase); Match match = regex.Match(input); if (match.Success) { result = match.Groups["Object"].Value; } } return result; } /// <summary> /// 返回有效价格 /// </summary> /// <param name="strPrice"></param> /// <returns></returns> public static decimal GetValidPrice(string strPrice) { decimal price = 0; try { if (!String.IsNullOrEmpty(strPrice)) { Regex regex = new Regex(@"^\d+(\.\d{1,2})?$", RegexOptions.IgnoreCase); Match match = regex.Match(strPrice); if (match.Success) { price = decimal.Parse(strPrice); } } } catch { } return price; }} |
希望本文所述对大家C#程序设计有所帮助。
