Question

我正在尝试从网页中检索数据。在网页上，只有句子。检索句子的正确方法是什么？我没试过就试过这个

 Dim webClient As New System.Net.WebClient
        Dim result As String = webClient.DownloadString("http://example.org")

        MsgBox(result)

Answer 1

好的，我认为你没有从HTTP调用中获得结果。这就是我的所作所为 - 对不起它的C＃，你必须翻译，但这可能接近你的需要：

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream receiveStream = response.GetResponseStream();
            StreamReader rdr = new StreamReader(receiveStream, Encoding.UTF8);

try
            {
                //Check that page downloaded OK
                if (response.StatusCode == HttpStatusCode.OK)
                {
              //Do something

}

        }
        catch (Exception xx)
        {
            //handle error
        }
        finally
        {
            response.Close();
        }

Answer 2

我曾经这样做过：

Imports System.Net
Imports System.IO
Imports System.IO.Compression

和

        Dim urlUri As New System.Uri("http://www.example.org/")
        Dim strResult as string = String.Empty

        Dim webHTTP As HttpWebRequest
        Try
            webHTTP = WebRequest.Create(urlUri)
            webHTTP.KeepAlive = False
        Catch ex As Exception
            Throw New Exception("An error occured while trying to create the request:" & vbCrLf & ex.Message)
            Exit Sub
        End Try

        Dim WebResponse As HttpWebResponse
        Try
            WebResponse = webHTTP.GetResponse()
        Catch ex As Exception
            Throw New Exception("An error occured while retrieving the response:" & vbCrLf & ex.Message)
            Exit Sub
        End Try

        Dim responseStream As Stream
        Try
            responseStream = WebResponse.GetResponseStream()
        Catch ex As Exception
            Throw New Exception("An error occured while retrieving the response stream:" & vbCrLf & ex.Message)
            Exit Sub
        End Try

        If (WebResponse.ContentEncoding.ToLower().Contains("gzip")) Then
            responseStream = New GZipStream(responseStream, CompressionMode.Decompress)
        ElseIf (WebResponse.ContentEncoding.ToLower().Contains("deflate")) Then
            responseStream = New DeflateStream(responseStream, CompressionMode.Decompress)
        End If

        Dim CHUNK_SIZE As Long = 3072
        Dim read(CHUNK_SIZE) As [Char]
        Dim reader As StreamReader
        Try
            reader = New StreamReader(responseStream, Encoding.Default)
        Catch ex As Exception
            Throw New Exception("An error occured while creating the streamreader:" & vbCrLf & ex.Message)
            Exit Sub
        End Try

        Dim count As Integer = reader.Read(read, 0, CHUNK_SIZE)
        Do While count > 0
            Dim str As New [String](read, 0, count)
            strResult &= str

            ReDim read(CHUNK_SIZE)
            count = reader.Read(read, 0, CHUNK_SIZE)
        Loop

        reader.Close()
        responseStream.Close()
        WebResponse.Close()

        Messagebox.Show(strResult)

简单从网页检索数据

2 个答案: