HttpWebRequest.GetResponse 方法

參考

定義

命名空間:: System.Net

組件:: System.Net.Requests.dll

組件:: System.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

傳回來自網際網路資源的回應。

public:
 override System::Net::WebResponse ^ GetResponse();

public override System.Net.WebResponse GetResponse ();

override this.GetResponse : unit -> System.Net.WebResponse

Public Overrides Function GetResponse () As WebResponse

傳回

WebResponse

包含來自網際網路資源回應的 WebResponse。

例外狀況

InvalidOperationException

此資料流已由先前對 BeginGetResponse(AsyncCallback, Object) 的呼叫所使用。

-或- TransferEncoding 設定為值，且 SendChunked 是 false。

ProtocolViolationException

Method 是 GET 或 HEAD，且 ContentLength 是大於或等於零，或 SendChunked 是 true。

-或- KeepAlive 是 true，AllowWriteStreamBuffering 是 false，ContentLength 為 -1，SendChunked 是 false，且 Method 為 POST 或 PUT。

-或- HttpWebRequest 具有實體主體，但 GetResponse() 方法在沒有呼叫 GetRequestStream() 方法的情況下呼叫。

-或- ContentLength 大於零，但應用程式不會寫入所有承諾的資料

NotSupportedException

要求快取驗證程式指出，此要求的回應可以由快取服務；不過，此要求包含要傳送到此伺服器的資料。傳送資料的要求不得使用此快取。如果您使用不正確實作的自訂快取驗證程式，便會發生這個例外狀況。

WebException

之前已呼叫過 Abort()。

-或- 要求的逾時時限已過期。

-或- 處理這個要求時發生錯誤。

範例

下列程式碼範例會取得要求的回應。

#using <System.dll>

using namespace System;
using namespace System::Net;
using namespace System::Text;
using namespace System::IO;

// Specify the URL to receive the request.
int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();
   HttpWebRequest^ request = dynamic_cast<HttpWebRequest^>(WebRequest::Create(args[1]));

   // Set some reasonable limits on resources used by this request
   request->MaximumAutomaticRedirections = 4;
   request->MaximumResponseHeadersLength = 4;

   // Set credentials to use for this request.
   request->Credentials = CredentialCache::DefaultCredentials;
   HttpWebResponse^ response = dynamic_cast<HttpWebResponse^>(request->GetResponse());
   Console::WriteLine("Content length is {0}", response->ContentLength);
   Console::WriteLine("Content type is {0}", response->ContentType);

   // Get the stream associated with the response.
   Stream^ receiveStream = response->GetResponseStream();

   // Pipes the stream to a higher level stream reader with the required encoding format.
   StreamReader^ readStream = gcnew StreamReader(receiveStream, Encoding::UTF8);
   Console::WriteLine("Response stream received.");
   Console::WriteLine(readStream->ReadToEnd());
   response->Close();
   readStream->Close();
}

/*
The output from this example will vary depending on the value passed into Main
but will be similar to the following:

Content length is 1542
Content type is text/html; charset=utf-8
Response stream received.
<html>
...
</html>

*/

using System;
using System.Net;
using System.Text;
using System.IO;

    public class Test
    {
        // Specify the URL to receive the request.
        public static void Main (string[] args)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(args[0]);

            // Set some reasonable limits on resources used by this request
            request.MaximumAutomaticRedirections = 4;
            request.MaximumResponseHeadersLength = 4;
            // Set credentials to use for this request.
            request.Credentials = CredentialCache.DefaultCredentials;
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            Console.WriteLine("Content length is {0}", response.ContentLength);
            Console.WriteLine("Content type is {0}", response.ContentType);

            // Get the stream associated with the response.
            Stream receiveStream = response.GetResponseStream();

            // Pipes the stream to a higher level stream reader with the required encoding format.
            StreamReader readStream = new StreamReader(receiveStream, Encoding.UTF8);

            Console.WriteLine("Response stream received.");
            Console.WriteLine(readStream.ReadToEnd());
            response.Close();
            readStream.Close();
        }
    }

/*
The output from this example will vary depending on the value passed into Main
but will be similar to the following:

Content length is 1542
Content type is text/html; charset=utf-8
Response stream received.
<html>
...
</html>

*/

Imports System.Net
Imports System.Text
Imports System.IO


    Public Class Test

        ' Specify the URL to receive the request.
        Public Shared Sub Main(ByVal args() As String)
        Dim request As HttpWebRequest = CType(WebRequest.Create(args(0)), HttpWebRequest)


        ' Set some reasonable limits on resources used by this request
        request.MaximumAutomaticRedirections = 4
        request.MaximumResponseHeadersLength = 4

        ' Set credentials to use for this request.
        request.Credentials = CredentialCache.DefaultCredentials

        Dim response As HttpWebResponse = CType(request.GetResponse(), HttpWebResponse)

        Console.WriteLine("Content length is {0}", response.ContentLength)
        Console.WriteLine("Content type is {0}", response.ContentType)

        ' Get the stream associated with the response.
        Dim receiveStream As Stream = response.GetResponseStream()

        ' Pipes the stream to a higher level stream reader with the required encoding format. 
        Dim readStream As New StreamReader(receiveStream, Encoding.UTF8)

        Console.WriteLine("Response stream received.")
        Console.WriteLine(readStream.ReadToEnd())
        response.Close()
        readStream.Close()
    End Sub
End Class
'
'The output from this example will vary depending on the value passed into Main 
'but will be similar to the following:
'
'Content length is 1542
'Content type is text/html; charset=utf-8
'Response stream received.
'...
'
'

備註

方法 GetResponse 會傳 WebResponse 回物件，其中包含來自網際網路資源的回應。傳回的實際實例是 HttpWebResponse ，而且可以型別傳送至該類別，以存取 HTTP 特定屬性。

ProtocolViolationException當類別上 HttpWebRequest 設定的屬性衝突時，會在數種情況下擲回。如果應用程式將屬性和 SendChunked 屬性設定 ContentLength 為 true ，然後傳送 HTTP GET 要求，就會發生這個例外狀況。如果應用程式嘗試將區塊化傳送至僅支援 HTTP 1.0 通訊協定的伺服器，但不支援此通訊協定，就會發生此例外狀況。如果應用程式嘗試在未設定 ContentLength 屬性的情況下傳送資料，或 SendChunked 是在 false 停用緩衝時，以及在屬性 (保持連線時 KeepAlive true ，就會發生此例外狀況) .

警告

您必須呼叫 Close 方法來關閉資料流程並釋放連線。無法這麼做可能會導致您的應用程式用盡連線。

使用 POST 方法時，您必須取得要求資料流程、寫入要張貼的資料，以及關閉資料流程。這個方法會封鎖等候內容張貼;如果沒有逾時設定，而且您未提供內容，則呼叫執行緒會無限期地封鎖。

注意

傳回相同回應物件的多個呼叫 GetResponse ;要求不會重新發出。

注意

您的應用程式無法混合特定要求的同步和非同步方法。如果您呼叫 GetRequestStream 方法，則必須使用 GetResponse 方法來擷取回應。

注意

WebException如果擲回，請使用 Response 例外狀況的和 Status 屬性來判斷伺服器的回應。

注意

在應用程式中啟用網路追蹤時，這個成員會輸出追蹤資訊。如需詳細資訊，請參閱.NET Framework中的網路追蹤。

注意

基於安全性考慮，預設會停用 Cookie。如果您想要使用 Cookie，請使用 CookieContainer 屬性來啟用 Cookie。

適用於

HttpWebRequest.GetResponse 方法

定義

傳回

例外狀況

範例

備註

適用於

另請參閱

其他資源