【C#】练习：采集新闻联播简介

[nilaoda]

思路

从网址 http://tv.cctv.com/lm/xwlb/ 获取内容

右侧网址的源代码：

代码

using System;
using System.IO;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;

namespace XWLBInfoFecher
{
    class Program
    {
        /// <summary>
        /// 获取某一天的新闻联播简介
        /// </summary>
        /// <param name="date">yyyy-MM-dd</param>
        /// <returns></returns>
        static string GetInfo(DateTime dateT)
        {
            string date = dateT.ToString("yyyyMMdd");
            string api = $"http://tv.cctv.com/lm/xwlb/day/{date}.shtml";
            WebClient web = new WebClient();
            web.Encoding = Encoding.UTF8;
            string webSource = web.DownloadString(api);
            Regex reg = new Regex(@"<li>[\s\S]*?<a href=\""(.*.shtml).*\"">[\s\S]*?title\"">(.*?)<\/div>[\s\S]*?<\/li>");
            webSource = web.DownloadString(reg.Match(webSource).Groups[1].Value);
            Regex descReg = new Regex(@"og:description\"" content=\""本期节目主要内容：([\s\S]*?)（《新闻联播》.*\""");
            return descReg.Match(webSource).Groups[1].Value.Replace("\r", "").Replace("\n", "").Trim();
        }

        static void Main(string[] args)
        {
            var startS = "2020-09-05";
            var endS = "2020-10-29";
            DateTime start = Convert.ToDateTime(startS);
            DateTime end = Convert.ToDateTime(endS);
            StringBuilder sb = new StringBuilder();
            while (true)
            {
                var line = $"　　{start.ToString("yyyyMMdd")}期：{GetInfo(start)}";
                Console.WriteLine(line);
                sb.AppendLine(line);
                start = start.AddDays(1);
                if (start.Equals(end))
                    break;
            }
            File.WriteAllText($"xwlb_{startS}_{endS}.txt", sb.ToString());
        }
    }
}

效果

知识点

• 正则表达式
• WebClient下载网页
• File写出文件
• DateTime获取下一天
• 内插表达式$"{var}"