C# 之【获取网页】

C#获取指定网页HTML原代码可使用 WebClient WebRequest HttpWebRequest 三种方式来实现。

当然也可使用webBrowse！在此就不研究webBrowse如何获取了。

WebClient

private string GetWebClient(string url)

{

    string strHTML = "";

    WebClient myWebClient = new WebClient();

    Stream myStream = myWebClient.OpenRead(url);

    StreamReader sr = new StreamReader(myStream, System.Text.Encoding.GetEncoding("utf-8"));

    strHTML = sr.ReadToEnd();

    myStream.Close();

    return strHTML;

}

WebRequest

private string GetWebRequest(string url)

{

    Uri uri = new Uri(url);

    WebRequest myReq = WebRequest.Create(uri);

    WebResponse result = myReq.GetResponse();

    Stream receviceStream = result.GetResponseStream();

    StreamReader readerOfStream = new StreamReader(receviceStream, System.Text.Encoding.GetEncoding("utf-8"));

    string strHTML = readerOfStream.ReadToEnd();

    readerOfStream.Close();

    receviceStream.Close();

    result.Close();

    return strHTML;

}

HttpWebRequest

private string GetHttpWebRequest(string url)

{

    Uri uri = new Uri(url);

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

    myReq.UserAgent = "User-Agent:Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705";

    myReq.Accept = "*/*";

    myReq.KeepAlive = true;

    myReq.Headers.Add("Accept-Language", "zh-cn,en-us;q=0.5");

    HttpWebResponse result = (HttpWebResponse)myReq.GetResponse();

    Stream receviceStream = result.GetResponseStream();

    StreamReader readerOfStream = new StreamReader(receviceStream, System.Text.Encoding.GetEncoding("utf-8"));

    string strHTML = readerOfStream.ReadToEnd();

    readerOfStream.Close();

    receviceStream.Close();

    result.Close();

    return strHTML;

}

注意“utf-8”应与指定网页的编码对应。

总结

可以看到HttpWebRequest 方式最复杂，但确提供了更多的选择性。

有的网站检测客户端的UserAgent！如163.com，你如果使用WebClient WebRequest方式获取时，将获取到的是错误提示页面内容。

而通过HttpWebRequest 就没问题。

源码下载：http://files.cnblogs.com/zjfree/GetHTML.rar

测试环境：WIN2003 + VS2005 + C# + winForm