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