asp.net使用正则表达式获取网页内容

Question

其实是老问题，网上也有些例子，但是都看不太懂，希望大家能讲解下，让我理解原理，随便给出答案更好O(∩_∩)O~网页是http://www.weather.com.cn/weather/101200101.shtml
要使用正则表达式获取比如地名，天气情况，风向，温度等信息，正则表达式如何写，往大家赐教。

Answer 1

楼上给正则 我给个抓取的
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using System.IO.Compression;
using System.Text.RegularExpressions;namespace WikiPageCreater.Common
{
    public class PageHelper
    {
        /// <summary>
        /// 根据 url 获取网页编码
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public static string GetEncoding(string url)
        {
            HttpWebRequest request = null;
            HttpWebResponse response = null;
            StreamReader reader = null;
            try
            {
                request = (HttpWebRequest)WebRequest.Create(url);
                request.Timeout = 20000;
                request.AllowAutoRedirect = false;                response = (HttpWebResponse)request.GetResponse();
                if (response.StatusCode == HttpStatusCode.OK && response.ContentLength < 1024 * 1024)
                {
                    if (response.ContentEncoding != null && response.ContentEncoding.Equals("gzip", StringComparison.InvariantCultureIgnoreCase))
                        reader = new StreamReader(new GZipStream(response.GetResponseStream(), CompressionMode.Decompress));
                    else
                        reader = new StreamReader(response.GetResponseStream(), Encoding.ASCII);                    string html = reader.ReadToEnd();                    Regex reg_charset = new Regex(@"charset\b\s*=\s*(?<charset>[^""]*)");
                    if (reg_charset.IsMatch(html))
                    {
                        return reg_charset.Match(html).Groups["charset"].Value;
                    }
                    else if (response.CharacterSet != string.Empty)
                    {
                        return response.CharacterSet;
                    }
                    else
                        return Encoding.Default.BodyName;
                }
            }
            catch
            {
            }
            finally
            {                if (response != null)
                {
                    response.Close();
                    response = null;
                }
                if (reader != null)
                    reader.Close();                if (request != null)
                    request = null;            }            return Encoding.Default.BodyName;
        }        /// <summary>
        /// 根据 url 和 encoding 获取当前url页面的 html 源代码        
       /// </summary>
        /// <param name="url"></param>
        /// <param name="encoding"></param>
        /// <returns></returns>
        public static string GetHtml(string url, Encoding encoding)
        {
            HttpWebRequest request = null;
            HttpWebResponse response = null;
            StreamReader reader = null;
            try
            {
                request = (HttpWebRequest)WebRequest.Create(url);
                request.Timeout = 20000;
                request.AllowAutoRedirect = false;                response = (HttpWebResponse)request.GetResponse();
                if (response.StatusCode == HttpStatusCode.OK && response.ContentLength < 1024 * 1024)
                {
                    if (response.ContentEncoding != null && response.ContentEncoding.Equals("gzip", StringComparison.InvariantCultureIgnoreCase))
                        reader = new StreamReader(new GZipStream(response.GetResponseStream(), CompressionMode.Decompress), encoding);
                    else
                        reader = new StreamReader(response.GetResponseStream(), encoding);
                    string html = reader.ReadToEnd();                    return html;
                }
            }
            catch
            {
            }
            finally
            {                if (response != null)
                {
                    response.Close();
                    response = null;
                }
                if (reader != null)
                    reader.Close();                if (request != null)
                    request = null;            }            return string.Empty;
        }
    }
}

Answer 2

没必要去抓取这些信息
太麻烦
这些东西 通过开放的web services就能得到
天气预报Web服务，数据来源于中国气象局Endpoint :http://www.webxml.com.cn/WebServices/WeatherWebService.asmxDisco :http://www.webxml.com.cn/WebServices/WeatherWebService.asmx?discoWSDL :http://www.webxml.com.cn/WebServices/WeatherWebService.asmx?wsdl
http://blog.csdn.net/fengyarongaa/article/details/6541109
http://www.cnblogs.com/wlb/archive/2009/04/18/1438019.html

Answer 3

就在这网站上搞个iframe的显示。反正你是一天一天的。。http://service.weather.com.cn/plugin/index.shtml

Answer 4

不要什么都用正则表达式，对于网页采集，可以先用正则对html进行预处理（去除script、style等标记），然后用xml处理，才是上策。

Answer 5

用xml，没听说过，您能解释下么？