用.NET 抓取一个页面

/// <summary>  02 /// Get a response as a string, given a uri string.  03 /// </summary>  04 /// <param name="uriArg">Specifies a uri such as "http://www.google.com" or @"file://X:\dir\myFile.html"</param>  05 /// <returns>web response as a string.</returns>  06 /// <example>  07 /// try  08 /// {  09 ///    string uri = "http://www.google.zzz"; // note bad uri with zzz to exercise exception.  10 ///    string s = GetWebPageResponse( uri );   11 ///    Console.WriteLine( s );  12 /// }  13 /// catch ( WebException ex )  14 /// {  15 ///    // wex.Message could be something like: The remote server returned an error: (404) Not Found.  16 ///    string s = string.Format( "Request: {0}\nResult: {1}", uri, ex.Message );  17 ///    Console.WriteLine( s );  18 /// }  19 /// </example>  20 static string GetWebPageResponse(string uriArg)  21 {  22     Stream responseStream = WebRequest.Create(uriArg).GetResponse().GetResponseStream();  23    24     StreamReader reader = new StreamReader(responseStream);  25    26     return reader.ReadToEnd();  27 }  28    29 /// <summary>  30 /// Similar to GetWebPageResponse(string uriArg), but uses a user/pw to log in.  31 /// </summary>  32 /// <param name="uriArg">e.g. "http://192.168.2.1"</param>  33 /// <param name="userArg">e.g. "root"</param>  34 /// <param name="pwArg">e.g. "admin"</param>  35 /// <returns>string containing the http response.</returns>  36 /// <example>  37 /// // Example to get a response with DHCP table from my LinkSys router.  38 /// string s = GetWebPageResponse( "http://192.168.2.1/DHCPTable.htm", "root", "admin" );  39 /// </example>  40 static string GetWebPageResponse(string uriArg, string userArg, string pwArg)  41 {  42     Uri uri = new Uri(uriArg);  43     HttpWebRequest req = (HttpWebRequest)WebRequest.Create(uri);  44     CredentialCache creds = new CredentialCache();  45    46     // See http://msdn.microsoft.com/en-us/library/system.directoryservices.protocols.authtype.aspx for list of types.  47     const string authType = "basic";  48    49     creds.Add(uri, authType, new NetworkCredential(userArg, pwArg));  50     req.PreAuthenticate = true;  51     req.Credentials = creds.GetCredential(uri, authType);  52    53     Stream responseStream = req.GetResponse().GetResponseStream();  54    55     StreamReader reader = new StreamReader(responseStream);  56    57     return reader.ReadToEnd();  58 }