数据采集之网页下载

string BoardStream = DownHtml("http://www.sina.com", System.Text.Encoding.GetEncoding("gb2312"));
StreamWriter saveAPage = new StreamWriter("aa.html", false, System.Text.Encoding.GetEncoding("gb2312"));//实例化写入类，保存路径假设为C:/a.html

saveAPage.Write(BoardStream);//创建写入任务

saveAPage.Flush();//写入文件（即清理缓存流）

saveAPage.Close();//关闭写入类的对象

/// <summary>
/// 下载网页
/// </summary>
/// <param name="Url">网址</param>
/// <param name="myEncoding">编码</param>
/// <returns>网页内容</returns>
public static string DownHtml(string Url, Encoding myEncoding)
{
try
{
HttpWebRequest loHttp = (HttpWebRequest)WebRequest.Create(Url);
loHttp.Timeout = 500;

HttpWebResponse loWebResponse = (HttpWebResponse)loHttp.GetResponse();
StreamReader loResponseStream = new StreamReader(loWebResponse.GetResponseStream(), myEncoding);
string html = loResponseStream.ReadToEnd();
loWebResponse.Close();
return html;
}
catch
{
return null;
}
}