C#基于正則表達(dá)式實(shí)現(xiàn)獲取網(wǎng)頁(yè)中所有信息的網(wǎng)頁(yè)抓取類(lèi)實(shí)例
本文實(shí)例講述了C#基于正則表達(dá)式實(shí)現(xiàn)獲取網(wǎng)頁(yè)中所有信息的網(wǎng)頁(yè)抓取類(lèi)。分享給大家供大家參考,具體如下:
類(lèi)的代碼:
using System;
using System.Data;
using System.Configuration;
using System.Net;
using System.IO;
using System.Text;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Threading;
using System.Web;
using System.Web.UI.MobileControls;
/// <summary>
/// 網(wǎng)頁(yè)類(lèi)
/// </summary>
public class WebPage
{
#region 私有成員
private Uri m_uri; //url
private List<Link> m_links; //此網(wǎng)頁(yè)上的鏈接
private string m_title; //標(biāo)題
private string m_html; //HTML代碼
private string m_outstr; //網(wǎng)頁(yè)可輸出的純文本
private bool m_good; //網(wǎng)頁(yè)是否可用
private int m_pagesize; //網(wǎng)頁(yè)的大小
private static Dictionary<string, CookieContainer> webcookies = new Dictionary<string, CookieContainer>();//存放所有網(wǎng)頁(yè)的Cookie
#endregion
#region 屬性
/// <summary>
/// 通過(guò)此屬性可獲得本網(wǎng)頁(yè)的網(wǎng)址,只讀
/// </summary>
public string URL
{
get
{
return m_uri.AbsoluteUri;
}
}
/// <summary>
/// 通過(guò)此屬性可獲得本網(wǎng)頁(yè)的標(biāo)題,只讀
/// </summary>
public string Title
{
get
{
if (m_title == "")
{
Regex reg = new Regex(@"(?m)<title[^>]*>(?<title>(?:\w|\W)*?)</title[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase);
Match mc = reg.Match(m_html);
if (mc.Success)
m_title = mc.Groups["title"].Value.Trim();
}
return m_title;
}
}
public string M_html
{
get
{
if (m_html == null)
{
m_html = "";
}
return m_html;
}
}
/// <summary>
/// 此屬性獲得本網(wǎng)頁(yè)的所有鏈接信息,只讀
/// </summary>
public List<Link> Links
{
get
{
if (m_links.Count == 0) getLinks();
return m_links;
}
}
/// <summary>
/// 此屬性返回本網(wǎng)頁(yè)的全部純文本信息,只讀
/// </summary>
public string Context
{
get
{
if (m_outstr == "") getContext(Int16.MaxValue);
return m_outstr;
}
}
/// <summary>
/// 此屬性獲得本網(wǎng)頁(yè)的大小
/// </summary>
public int PageSize
{
get
{
return m_pagesize;
}
}
/// <summary>
/// 此屬性獲得本網(wǎng)頁(yè)的所有站內(nèi)鏈接
/// </summary>
public List<Link> InsiteLinks
{
get
{
return getSpecialLinksByUrl("^http://" + m_uri.Host, Int16.MaxValue);
}
}
/// <summary>
/// 此屬性表示本網(wǎng)頁(yè)是否可用
/// </summary>
public bool IsGood
{
get
{
return m_good;
}
}
/// <summary>
/// 此屬性表示網(wǎng)頁(yè)的所在的網(wǎng)站
/// </summary>
public string Host
{
get
{
return m_uri.Host;
}
}
#endregion
/// <summary>
/// 從HTML代碼中分析出鏈接信息
/// </summary>
/// <returns>List<Link></returns>
private List<Link> getLinks()
{
if (m_links.Count == 0)
{
Regex[] regex = new Regex[2];
regex[0] = new Regex(@"<a\shref\s*=""(?<URL>[^""]*).*?>(?<title>[^<]*)</a>", RegexOptions.IgnoreCase | RegexOptions.Singleline);
regex[1] = new Regex("<[i]*frame[^><]+src=(\"|')?(?<url>([^>\"'\\s)])+)(\"|')?[^>]*>", RegexOptions.IgnoreCase);
for (int i = 0; i < 2; i++)
{
Match match = regex[i].Match(m_html);
while (match.Success)
{
try
{
string url = HttpUtility.UrlDecode(new Uri(m_uri, match.Groups["URL"].Value).AbsoluteUri);
string text = "";
if (i == 0) text = new Regex("(<[^>]+>)|(\\s)|( )|&|\"", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(match.Groups["text"].Value, "");
Link link = new Link();
link.Text = text;
link.NavigateUrl = url;
m_links.Add(link);
}
catch (Exception ex) { Console.WriteLine(ex.Message); };
match = match.NextMatch();
}
}
}
return m_links;
}
/// <summary>
/// 此私有方法從一段HTML文本中提取出一定字?jǐn)?shù)的純文本
/// </summary>
/// <param name="instr">HTML代碼</param>
/// <param name="firstN">提取從頭數(shù)多少個(gè)字</param>
/// <param name="withLink">是否要鏈接里面的字</param>
/// <returns>純文本</returns>
private string getFirstNchar(string instr, int firstN, bool withLink)
{
if (m_outstr == "")
{
m_outstr = instr.Clone() as string;
m_outstr = new Regex(@"(?m)<script[^>]*>(\w|\W)*?</script[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
m_outstr = new Regex(@"(?m)<style[^>]*>(\w|\W)*?</style[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
m_outstr = new Regex(@"(?m)<select[^>]*>(\w|\W)*?</select[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
if (!withLink) m_outstr = new Regex(@"(?m)<a[^>]*>(\w|\W)*?</a[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
Regex objReg = new System.Text.RegularExpressions.Regex("(<[^>]+?>)| ", RegexOptions.Multiline | RegexOptions.IgnoreCase);
m_outstr = objReg.Replace(m_outstr, "");
Regex objReg2 = new System.Text.RegularExpressions.Regex("(\\s)+", RegexOptions.Multiline | RegexOptions.IgnoreCase);
m_outstr = objReg2.Replace(m_outstr, " ");
}
return m_outstr.Length > firstN ? m_outstr.Substring(0, firstN) : m_outstr;
}
#region 公有文法
/// <summary>
/// 此公有方法提取網(wǎng)頁(yè)中一定字?jǐn)?shù)的純文本,包括鏈接文字
/// </summary>
/// <param name="firstN">字?jǐn)?shù)</param>
/// <returns></returns>
public string getContext(int firstN)
{
return getFirstNchar(m_html, firstN, true);
}
/// <summary>
/// 此公有方法從本網(wǎng)頁(yè)的鏈接中提取一定數(shù)量的鏈接,該鏈接的URL滿足某正則式
/// </summary>
/// <param name="pattern">正則式</param>
/// <param name="count">返回的鏈接的個(gè)數(shù)</param>
/// <returns>List<Link></returns>
public List<Link> getSpecialLinksByUrl(string pattern, int count)
{
if (m_links.Count == 0) getLinks();
List<Link> SpecialLinks = new List<Link>();
List<Link>.Enumerator i;
i = m_links.GetEnumerator();
int cnt = 0;
while (i.MoveNext() && cnt < count)
{
if (new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase).Match(i.Current.NavigateUrl).Success)
{
SpecialLinks.Add(i.Current);
cnt++;
}
}
return SpecialLinks;
}
/// <summary>
/// 此公有方法從本網(wǎng)頁(yè)的鏈接中提取一定數(shù)量的鏈接,該鏈接的文字滿足某正則式
/// </summary>
/// <param name="pattern">正則式</param>
/// <param name="count">返回的鏈接的個(gè)數(shù)</param>
/// <returns>List<Link></returns>
public List<Link> getSpecialLinksByText(string pattern, int count)
{
if (m_links.Count == 0) getLinks();
List<Link> SpecialLinks = new List<Link>();
List<Link>.Enumerator i;
i = m_links.GetEnumerator();
int cnt = 0;
while (i.MoveNext() && cnt < count)
{
if (new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase).Match(i.Current.Text).Success)
{
SpecialLinks.Add(i.Current);
cnt++;
}
}
return SpecialLinks;
}
/// <summary>
/// 這公有方法提取本網(wǎng)頁(yè)的純文本中滿足某正則式的文字 by 何問(wèn)起
/// </summary>
/// <param name="pattern">正則式</param>
/// <returns>返回文字</returns>
public string getSpecialWords(string pattern)
{
if (m_outstr == "") getContext(Int16.MaxValue);
Regex regex = new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase);
Match mc = regex.Match(m_outstr);
if (mc.Success)
return mc.Groups[1].Value;
return string.Empty;
}
#endregion
#region 構(gòu)造函數(shù)
private void Init(string _url)
{
try
{
m_uri = new Uri(_url);
m_links = new List<Link>();
m_html = "";
m_outstr = "";
m_title = "";
m_good = true;
if (_url.EndsWith(".rar") || _url.EndsWith(".dat") || _url.EndsWith(".msi"))
{
m_good = false;
return;
}
HttpWebRequest rqst = (HttpWebRequest)WebRequest.Create(m_uri);
rqst.AllowAutoRedirect = true;
rqst.MaximumAutomaticRedirections = 3;
rqst.UserAgent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";
rqst.KeepAlive = true;
rqst.Timeout = 10000;
lock (WebPage.webcookies)
{
if (WebPage.webcookies.ContainsKey(m_uri.Host))
rqst.CookieContainer = WebPage.webcookies[m_uri.Host];
else
{
CookieContainer cc = new CookieContainer();
WebPage.webcookies[m_uri.Host] = cc;
rqst.CookieContainer = cc;
}
}
HttpWebResponse rsps = (HttpWebResponse)rqst.GetResponse();
Stream sm = rsps.GetResponseStream();
if (!rsps.ContentType.ToLower().StartsWith("text/") || rsps.ContentLength > 1 << 22)
{
rsps.Close();
m_good = false;
return;
}
Encoding cding = System.Text.Encoding.Default;
string contenttype = rsps.ContentType.ToLower();
int ix = contenttype.IndexOf("charset=");
if (ix != -1)
{
try
{
cding = System.Text.Encoding.GetEncoding(rsps.ContentType.Substring(ix + "charset".Length + 1));
}
catch
{
cding = Encoding.Default;
}
//該處視情況而定 有的需要解碼
//m_html = HttpUtility.HtmlDecode(new StreamReader(sm, cding).ReadToEnd());
m_html = new StreamReader(sm, cding).ReadToEnd();
}
else
{
//該處視情況而定 有的需要解碼
//m_html = HttpUtility.HtmlDecode(new StreamReader(sm, cding).ReadToEnd());
m_html = new StreamReader(sm, cding).ReadToEnd();
Regex regex = new Regex("charset=(?<cding>[^=]+)?\"", RegexOptions.IgnoreCase);
string strcding = regex.Match(m_html).Groups["cding"].Value;
try
{
cding = Encoding.GetEncoding(strcding);
}
catch
{
cding = Encoding.Default;
}
byte[] bytes = Encoding.Default.GetBytes(m_html.ToCharArray());
m_html = cding.GetString(bytes);
if (m_html.Split('?').Length > 100)
{
m_html = Encoding.Default.GetString(bytes);
}
}
m_pagesize = m_html.Length;
m_uri = rsps.ResponseUri;
rsps.Close();
}
catch (Exception ex)
{
}
}
public WebPage(string _url)
{
string uurl = "";
try
{
uurl = Uri.UnescapeDataString(_url);
_url = uurl;
}
catch { };
Init(_url);
}
#endregion
}
調(diào)用:
WebPage webInfo = new WebPage("http://hovertree.net/");
webInfo.Context;//不包含html標(biāo)簽的所有內(nèi)容
webInfo.M_html;//包含html標(biāo)簽的內(nèi)容 by 何問(wèn)起
PS:這里再為大家提供2款非常方便的正則表達(dá)式工具供大家參考使用:
JavaScript正則表達(dá)式在線測(cè)試工具:
http://tools.jb51.net/regex/javascript
正則表達(dá)式在線生成工具:
http://tools.jb51.net/regex/create_reg
更多關(guān)于C#相關(guān)內(nèi)容感興趣的讀者可查看本站專(zhuān)題:《C#正則表達(dá)式用法總結(jié)》、《C#編碼操作技巧總結(jié)》、《C#中XML文件操作技巧匯總》、《C#常見(jiàn)控件用法教程》、《WinForm控件用法總結(jié)》、《C#數(shù)據(jù)結(jié)構(gòu)與算法教程》、《C#面向?qū)ο蟪绦蛟O(shè)計(jì)入門(mén)教程》及《C#程序設(shè)計(jì)之線程使用技巧總結(jié)》
希望本文所述對(duì)大家C#程序設(shè)計(jì)有所幫助。
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欄 目:C#教程
本文標(biāo)題:C#基于正則表達(dá)式實(shí)現(xiàn)獲取網(wǎng)頁(yè)中所有信息的網(wǎng)頁(yè)抓取類(lèi)實(shí)例
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