本篇是系列的第二篇，主要介绍如何分析有声读物每集的链接地址，本文希望阅读者根据文章就能自己写出程序，所以写的比较详细，大家见谅，软件的下载地址。
一、咱们随便找一本评书进入其详细页，我们要获得评书的简介和剧集列表两部分内容，具体页面如下:
分析一下Html代码，简介是包含在<div class="book02 padding5 line5">简介内容</div>中，但需要注意，里包含了br、script等html标签,所以抓取内容后，需要清除一下html标签。
另外有一点需要注意，由于简介中可能含有div，所以正则表达式用贪婪模式或非贪婪模式都可能出现无法正确匹配，所以要保证唯一性，注意下面粗体的部分。
获取简介的正则表达式：<div class=""book02 padding5 line5"">(?<Summary>[\s\S]*?)</div>\r\n<div class=""js[\d]*"">
PS:使用IE开发人员工具（F12）时发现一个问题，它会对代码进行整理，所以你看到内容有可能不是网页的真实内容，如下面两幅图
title,href的顺序不一样，Chrome中显示的是实际代码顺序。
具体的正则表达式：<div class=""b2""><a href=""(?<SubPath>[\d\w]*)/play_[\d]*_(?<Number>[\d]*).htm""(\s*title=""[\s\S]*?.mp3"")*>(?<Title>[\s\S]*?).mp3</a></div>
二、评书下载界面如下 :
三、主要的代码
Sound.cs
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using System;
using System.Collections.Generic; using System.Linq; using System.Text; namespace psDownload { /// <summary> /// 有声读物类 /// </summary> public class Sound { /// <summary> /// 编号 /// </summary> public int ID { set; get; } /// <summary> /// 标题 /// </summary> public string Title { set; get; } /// <summary> /// 演播者 /// </summary> public string Performer { set; get; } /// <summary> /// 详细页网址 /// </summary> public string Url { set; get; } /// <summary> /// MP3的下载地址 /// </summary> public string DownUrl { set; get; } /// <summary> /// 状态 0：等待下载 1：下载成功 -1：下载失败 /// </summary> public int Status { set; get; } /// <summary> /// 错误详情 /// </summary> public string Error { set; get; } } } |
C# Code
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//评书的名称、详细页网址、所属分类、文件输出路径
private string _title = "", _url = "", _category = "", _outpath = ""; //评书集数列表，Sound是一个自己写的类。 private List<Sound> _list = new List<Sound>(); public frmDetail(string Title, string Url, string OutPath) { InitializeComponent(); this._title = Title; this._url = Url; this._outpath = OutPath; //获取评书所属的分类，后面需要用到，其实从上一个窗体传过来也行。 Match match = Regex.Match(Url, @"http://www.tingchina.com/(?<Category>[\w]*)/disp_[\d]*.htm", RegexOptions.IgnoreCase | RegexOptions.Multiline); if (match.Success) { this._category = match.Groups["Category"].Value; } } private void frmDetail_Load(object sender, EventArgs e) { this.Text = this._title; this.lbl_Title.Text = this._title; this.llbl_Url.Text = this._url; //发送异步请求，获取评书的详细信息和剧集列表 HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(this._url); req.Timeout = 15 * 1000; req.Method = "GET"; req.BeginGetResponse(new AsyncCallback(ResponseCallBack), req); } /// <summary> /// http异步请求的回调函数，分析网页，获得评书的简介、剧集列表等信息 /// </summary> /// <param name="result"></param> public void ResponseCallBack(IAsyncResult result) { string Html = ""; HttpWebRequest req = (HttpWebRequest)result.AsyncState; try { using (HttpWebResponse response = (HttpWebResponse)req.EndGetResponse(result)) { Stream resStream = response.GetResponseStream(); StreamReader sr = new StreamReader(resStream, Encoding.GetEncoding("GB2312")); Html = sr.ReadToEnd(); } } catch (Exception ex) { if (IsDisposed || !this.IsHandleCreated) return; this.Invoke(new Action(() => { MessageBox.Show("抓取网页出现异常,原因:" + ex.Message); })); return; } //动态生成Label控件所需的字体 Font font = new Font("微软雅黑", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134))); //获取评书的简介 Match ms_Summary = Regex.Match(Html, @"<div class=""book02 padding5 line5"">(?<Summary>[\s\S]*?)</div>\r\n<div class=""js[\d]*"">", RegexOptions.IgnoreCase | RegexOptions.Multiline); if (ms_Summary.Success) { if (IsDisposed || !this.IsHandleCreated) return; this.Invoke(new Action(() => { this.txt_Summary.Text = ClearHtml(ms_Summary.Groups["Summary"].Value); })); } //正则表达式分析网页，获取评书的剧集。 MatchCollection ms = Regex.Matches(Html, @"<div class=""b2""><a href=""(?<SubPath>[\d\w]*)/play_[\d]*_(?<Number>[\d]*).htm""(\s*title=""[\s\S]*?.mp3"")*>(?<Title>[\s\S]*?).mp3</a></div>", RegexOptions.IgnoreCase | RegexOptions.Multiline); if (ms.Count > 0) { //最大宽度 int MaxWidth = 0; this._list.Clear(); foreach (Match m in ms) { Sound sound = new Sound(); sound.ID = int.Parse(m.Groups["Number"].Value); sound.Title = m.Groups["Title"].Value; sound.Url = "http://www.tingchina.com/" + this._category + "/" + m.Groups["SubPath"].Value + "/play_" + m.Groups["SubPath"].Value + "_" + m.Groups["Number"].Value + ".htm"; this._list.Add(sound); //获取字体的大小，找到最宽的那个条记录 Size size = TextRenderer.MeasureText(m.Groups["Title"].Value, font); if (size.Width > MaxWidth) { MaxWidth = size.Width; } } if (IsDisposed || !this.IsHandleCreated) return; this.Invoke(new Action(() => { //循环动态生成查询结果. foreach (Sound sound in _list) { Panel pnl = new Panel(); Label lbl = new Label(); lbl.Name = "lbl_" + sound.ID.ToString(); lbl.Text = sound.Title; lbl.Tag = sound.Url; lbl.Cursor = System.Windows.Forms.Cursors.Hand; lbl.Margin = new System.Windows.Forms.Padding(15, 0, 0, 10); lbl.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(0)))), ((int)(((byte)(192)))), ((int)(((byte)(0))))); lbl.Font = font; lbl.Width = MaxWidth; lbl.Click += new EventHandler(lbl_Click); pnl.Controls.Add(lbl); PictureBox pic = new PictureBox(); pic.Name = "pic_" + sound.ID.ToString(); pic.Left = lbl.Width; pic.Top = 3; pic.SizeMode = PictureBoxSizeMode.Zoom; pic.Height = 16; pic.Width = 16; pnl.Name = "pnl_" + sound.ID.ToString(); pnl.Tag = sound; pnl.Controls.Add(pic); pnl.AutoSize = true; this.fpnl_Content.Controls.Add(pnl); Application.DoEvents(); } this.btn_Download.Enabled = true; this.btn_Download.ForeColor = Color.Black; this.btn_Download.Text = "批量下载"; this.btn_Download.Focus(); })); } else { if (IsDisposed || !this.IsHandleCreated) return; this.Invoke(new Action(() => { MessageBox.Show("分析网页失败，请检查。"); })); } } /// <summary> /// 清除字符串中HTML控制字符 /// </summary> /// <param name="s">要清除的字符串</param> /// <returns></returns> public static string ClearHtml(string s) { if (s == null) return null; return HtmlDecode(Regex.Replace(s, @"(<[^>]+>)|[\r\n]", "", RegexOptions.IgnoreCase | RegexOptions.Singleline)); } private static string HtmlDecodeMatchEvaluator(Match m) { switch (m.Value) { case "<": return "<"; case ">": return ">"; case "&": return "&"; case """: return "\""; case " ": return "\u0020"; default: return m.Value; } } /// <summary> /// HTML解码 /// </summary> /// <param name="s"></param> /// <returns></returns> private static string HtmlDecode(string s) { return Regex.Replace(s, "(<)|(>)|(&)|(")|( )", new MatchEvaluator(HtmlDecodeMatchEvaluator), RegexOptions.Singleline | RegexOptions.IgnoreCase); } |
未完待续...
作者：相信的勇气
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勤奋的男人和爱笑的女人,运气一般都不会太差。
