一、前言

今天在网上偶遇一款html解析利器HtmlAgilityPack，免费下载地址：入口。

HtmlAgilityPack是.net下的一个HTML解析类库，支持用XPath来解析HTML。通过该类库，先通过浏览器获取到xpath获取到节点内容然后再通过正则表达式匹配到所需要的内容，无论是开发速度，还是运行效率都有提升。

二、效果图

这里拿我的博客主页试试手，先看解析结果：

三、程序分析

1、主程序如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using HtmlAgilityPack;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string uri = @"https://blog.csdn.net/marcopro/article/list/1";
            HttpWebRequestHelper httpReq = new HttpWebRequestHelper();
            string strHtml = httpReq.Get(uri);
            HtmlDocument htmlDoc = new HtmlDocument();
            htmlDoc.LoadHtml(strHtml);
            HtmlNodeCollection articleList = htmlDoc.DocumentNode.SelectNodes("//div[@class='article-item-box csdn-tracking-statistics']");
            if (articleList.Count > 0)
            {
                foreach (var item in articleList)
                {
                    string itemHtml = item.InnerHtml;
                    Regex re = new Regex(@"<a[^>]*href=(""(?<href>[^""]*)""|'(?<href>[^']*)'|(?<href>[^\s>]*))[^>]*>(?<text>.*?)</a>", RegexOptions.IgnoreCase | RegexOptions.Singleline);
                    Match m = re.Match(itemHtml);
                    if (m.Success)
                    {
                        string link = m.Groups["href"].Value;
                        string text = Regex.Replace(m.Groups["text"].Value, "<[^>]*>", "");
                        text = text.Replace("原创", "").Trim();
                        Console.WriteLine("link:{0}\ntext:{1}", link, text);
                    }
                }
            }
            Console.Read();
        }
    }
}

2、获取页面html

string uri = @"https://blog.csdn.net/marcopro/article/list/1";
HttpWebRequestHelper httpReq = new HttpWebRequestHelper();
string strHtml = httpReq.Get(uri);

这里获取html的时候需要注意编码问题，不让会出现中文乱码，这里我用了utf-8编码

/// <summary>
/// 获取页面html   encodingname:gb2312/utf-8
/// </summary>
/// <param name="uri">访问url</param>
/// <returns></returns>
public string Get(string uri)
{
    return Get(uri, uri, "utf-8");
}

/// <summary>
/// 获取页面html   encodingname:gb2312
/// </summary>
/// <param name="uri">访问url</param>
/// <param name="refererUri">来源url</param>
/// <returns></returns>
public string Get(string uri, string refererUri)
{
    return Get(uri, refererUri, "utf-8");
}

/// <summary>
/// 获取页面html
/// </summary>
/// <param name="uri">访问url</param>
/// <param name="refererUri">来源url</param>
/// <param name="encodingName">编码名称  例如：gb2312</param>
/// <returns></returns>
public string Get(string uri, string refererUri, string encodingName)
{
    return Get(uri, refererUri, encodingName, (WebProxy)null);
}

/// <summary>
/// 获取页面html
/// </summary>
/// <param name="uri">访问url</param>
/// <param name="refererUri">来源url</param>
/// <param name="encodingName">编码名称  例如：gb2312</param>
/// <param name="webproxy">代理</param>
/// <returns></returns>
public string Get(string uri, string refererUri, string encodingName, WebProxy webproxy)
{
    string html = string.Empty;

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);

    request.ContentType = "text/html;charset=" + encodingName;
    request.Method = "Get";
    request.CookieContainer = cookieContainer;

    if (null != webproxy)
    {
        request.Proxy = webproxy;
        if (null != webproxy.Credentials)
            request.UseDefaultCredentials = true;
    }

    if (!string.IsNullOrEmpty(refererUri))
        request.Referer = refererUri;

    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    {
        using (Stream streamResponse = response.GetResponseStream())
        {
            using (StreamReader streamResponseReader = new StreamReader(streamResponse, Encoding.GetEncoding(encodingName)))
            {
                html = streamResponseReader.ReadToEnd();
            }
        }
    }
    return html;
}

2、获取博客清单html

根据获取的html源码稍作分析会发现，博客园的博客清单都有标签class='article-item-box csdn-tracking-statistics'，所以通过HtmlAgilityPack的解析，直接获取所有博客清单div。

HtmlDocument htmlDoc = new HtmlDocument();
htmlDoc.LoadHtml(strHtml);
HtmlNodeCollection articleList = htmlDoc.DocumentNode.SelectNodes("//div[@class='article-item-box csdn-tracking-statistics']");

3、解析博客标题和链接地址

HtmlAgilityPack解析出来的只是代码段，还需要把博客的标题和链接抽取出来，这里用到了则正则表达式来处理

if (articleList.Count > 0)
{
    foreach (var item in articleList)
    {
        string itemHtml = item.InnerHtml;
        Regex re = new Regex(@"<a[^>]*href=(""(?<href>[^""]*)""|'(?<href>[^']*)'|(?<href>[^\s>]*))[^>]*>(?<text>.*?)</a>", RegexOptions.IgnoreCase | RegexOptions.Singleline);
        Match m = re.Match(itemHtml);
        if (m.Success)
        {
            string link = m.Groups["href"].Value;
            string text = Regex.Replace(m.Groups["text"].Value, "<[^>]*>", "");
            text = text.Replace("原创", "").Trim();
            Console.WriteLine("link:{0}\ntext:{1}", link, text);
        }
    }
}

至此，就解析出完整的博客清单了。