C#简单爬虫爬取图片并保存本地

static void Main(string[] args)
{

    var page = 1;//抓取的页数

    //抓取网页资源
    for (int i = 1; i <= page; i++)
    {
        string str = GetHtmlStr($"https://fabiaoqing.com/biaoqing/lists/page/{i}.html", "UTF8");
        //匹配图片的正则表达式    
        string regstr = "http://wx[1-4].sinaimg.cn/bmiddle/.+?.[jg][pi][fg]";
        foreach (Match match in Regex.Matches(str, regstr))
        //使用正则表达式解析网页文本，获得图片地址     
        {
            //下载图片
            SaveAsWebImg(match.Value);
        }
    }
    Console.ReadKey();
    Console.WriteLine("已执行结束，按任意键退出！");

}

/// <summary>  
/// 获取网页的HTML码  
/// </summary>  
/// <param name="url">链接地址</param>  
/// <param name="encoding">编码类型</param>  
/// <returns></returns>  
public static string GetHtmlStr(string url, string encoding)
{
    string htmlStr = "";
    if (!String.IsNullOrEmpty(url))
    {
        WebRequest request = WebRequest.Create(url);            //实例化WebRequest对象  
        WebResponse response = request.GetResponse();           //创建WebResponse对象  
        Stream datastream = response.GetResponseStream();       //创建流对象  
        Encoding ec = Encoding.Default;
        if (encoding == "UTF8")
        {
            ec = Encoding.UTF8;
        }
        else if (encoding == "Default")
        {
            ec = Encoding.Default;
        }
        StreamReader reader = new StreamReader(datastream, ec);
        htmlStr = reader.ReadToEnd();                           //读取数据  
        reader.Close();
        datastream.Close();
        response.Close();
    }
    return htmlStr;
}

/// <summary> 
/// 下载网站图片 
/// </summary> 
/// <param name="picUrl"></param> 
/// <returns></returns> 
public static string SaveAsWebImg(string picUrl)
{
    string result = "";
    //设置保存目录
    string path = AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"/File/";
    //不存在目录则创建
    if (!Directory.Exists(path))
    {
        //创建目录
        Directory.CreateDirectory(path);
    }
    try
    {
        //判断图片是否为空或者null
        if (!String.IsNullOrEmpty(picUrl))
        {
            //伪随机数生成器
            Random rd = new Random();
            //获取当前日期时间
            DateTime nowTime = DateTime.Now;
            //获取URL扩展名
            var Extension = Path.GetExtension(picUrl);
            //自定义文件名
            string fileName = nowTime.Month.ToString() + nowTime.Day.ToString() + nowTime.Hour.ToString() + nowTime.Minute.ToString() + nowTime.Second.ToString() + rd.Next(1000, 1000000) + Extension;
            WebClient webClient = new WebClient();
            //下载url链接文件，并指定到本地的文件夹路径和文件名称
            webClient.DownloadFile(picUrl, path + fileName);
            //返回结果
            result = fileName;
        }
    }catch(Exception ex) {
        Console.WriteLine(ex.Message);
    }
    return result;
}