有时我们需要采集一些信息到自己的数据库，本地磁盘，我们经常使用的是WebClient,WebRequest等等，今天主要说一下，对于一个ＵＲＩ地址，采集这个页面上所有的图像资源，下面是源代码，供大家参考，学习。
/// <summary> /// 下载指定ＵＲＬ下的所有图片 /// </summary> public class WebPageImage { /// <summary> /// 获取网页中全部图片 /// </summary> /// <param>网页地址</param> /// <param>网页编码，为空自动判断</param> /// <returns>全部图片显示代码</returns> public string getImages(string url, string charSet) { string s = getHtml(url, charSet); return getPictures(s, url); } /// <summary> /// 获取网页中全部图片 /// </summary> /// <param>网址</param> /// <returns>全部图片代码</returns> public string getImages(string url) { return getImages(url, ""); } string doman(string url) { Uri u = new Uri(url); return u.Host; } /// <summary> /// 获取网页内容 /// </summary> /// <param>网站地址</param> /// <param>目标网页的编码,如果传入的是null或者"",那就自动分析网页的编码 </param> /// <returns></returns> string getHtml(string url, string charSet) { WebClient myWebClient = new WebClient(); //创建WebClient实例myWebClient // 需要注意的： //有的网页可能下不下来，有种种原因比如需要cookie,编码问题等等 //这是就要具体问题具体分析比如在头部加入cookie // webclient.Headers.Add("Cookie", cookie); //这样可能需要一些重载方法。根据需要写就可以了 //获取或设置用于对向 Internet 资源的请求进行身份验证的网络凭据。 myWebClient.Credentials = CredentialCache.DefaultCredentials; //如果服务器要验证用户名,密码 //NetworkCredential mycred = new NetworkCredential(struser, strpassword); //myWebClient.Credentials = mycred; //从资源下载数据并返回字节数组。（加@是因为网址中间有"https://www.jb51.net/"符号） byte[] myDataBuffer = myWebClient.DownloadData(url); string strWebData = Encoding.Default.GetString(myDataBuffer); //获取网页字符编码描述信息 Match charSetMatch = Regex.Match(strWebData, "<meta([^<]*)charset=([^<]*)\"", RegexOptions.IgnoreCase | RegexOptions.Multiline); string webCharSet = charSetMatch.Groups[2].Value.Replace("\"", ""); if (charSet == null || charSet == "") charSet = webCharSet; if (charSet != null && charSet != "" && Encoding.GetEncoding(charSet) != Encoding.Default) strWebData = Encoding.GetEncoding(charSet).GetString(myDataBuffer); return strWebData; } string getPictures(string data, string url) { MatchCollection ps = Regex.Matches(data, @"<img\b[^<>]*?\bsrc[\s\t\r\n]*=[\s\t\r\n]*[""']?[\s\t\r\n]*(?<imgUrl>[^\s\t\r\n""'<>]*)[^<>]*?/?[\s\t\r\n]*>"); string s = string.Empty; for (int i = 0; i < ps.Count; i++) { pictures p = new pictures(ps[i].Value, url); s += p.GetHtml + "<br />" + Environment.NewLine; } return s; } /// <summary> /// 图片实体 /// 图片文件属性处理类 /// </summary> public class pictures { public pictures(string strHtml, string baseUrl) { _html = strHtml; Uri u1 = new Uri(baseUrl); _doman = u1.Host; _baseUrl = u1.Scheme + "://" + _doman; setSrc(); } private string _html = string.Empty; private string _baseUrl = string.Empty; private string _doman = string.Empty; public string GetHtml { get { return _html; } } public string Alt { get { return GetAttribute("alt")[0]; } } public string Src { get { string s = GetAttribute("src")[0]; return s; } } /// <summary> /// 根据基路径把相对路径转换成绝对径 /// </summary> /// <param>基础路径</param> /// <param>待转换的相对路径</param> /// <returns>绝对路径</returns> public string absUrl(string baseUrl, string u) { Uri ub = new Uri(baseUrl); Uri ua = new Uri(ub, u); return ua.AbsoluteUri; } private void setSrc() { string strPattern = @"src[\s\t\r\n]*=[\s\t\r\n]*[""']?\S+[""']?"; string src = GetAttribute("src")[0].ToLower(); if (!(src.IndexOf("http://") == 0 || src.IndexOf("https://") == 0) && _baseUrl.Length > 10) { src = absUrl(_baseUrl, src); string s = "src=\"" + src + "\""; _html = Regex.Replace(_html, strPattern, s); } } /// <summary> /// 获取HTML代码中标签属性 /// </summary> /// <param>HTML代码</param> /// <param>属性名称</param> /// <returns>属性值集合</returns> private string[] GetAttribute(string strAttributeName) { List<string> lstAttribute = new List<string>(); string strPattern = string.Format( @"{0}[\s\t\r\n]*=[\s\t\r\n]*[""']?\S+[""']?", strAttributeName ); MatchCollection matchs = Regex.Matches(_html, strPattern, RegexOptions.IgnoreCase); foreach (Match m in matchs) { lstAttribute.Add(m.Value.Split('=')[1].Replace("\"", "").Replace("'", "")); } if (lstAttribute.Count == 0) lstAttribute.Add(""); return lstAttribute.ToArray(); } } }
调用：
new WebPageImage().getImages()
结果：
