ServicePoint 类

定义

public ref class ServicePoint

public class ServicePoint

type ServicePoint = class

Public Class ServicePoint

继承

Object

ServicePoint

示例

下面的代码示例创建一个 ServicePoint 连接到 URI www.contoso.com的对象。

// This example shows how to use the ServicePoint and ServicePointManager classes.
// The ServicePointManager class uses the ServicePoint class to manage connections
// to a remote host. The networking classes reuse service points for all
// requests to a given URI. In fact, the same ServicePoint object
// is used to issue requests to Internet resources identified by the same
// scheme identifier (for example,  HTTP) and host fragment (for example,  www.contoso.com).
// This should improve your application performance.
// Reusing service points in this way can help improve application performance.
using System;
using System.Net;
using System.Threading;
using System.Text.RegularExpressions;

namespace Mssc.Services.ConnectionManagement
{
    class TestServicePoint
    {
        private static void ShowProperties(ServicePoint sp)
        {
            Console.WriteLine("Done calling FindServicePoint()...");

            // Display the ServicePoint Internet resource address.
            Console.WriteLine("Address = {0} ", sp.Address.ToString());

            // Display the date and time that the ServicePoint was last
            // connected to a host.
            Console.WriteLine("IdleSince = " + sp.IdleSince.ToString());

            // Display the maximum length of time that the ServicePoint instance
            // is allowed to maintain an idle connection to an Internet
            // resource before it is recycled for use in another connection.
            Console.WriteLine("MaxIdleTime = " + sp.MaxIdleTime);

            Console.WriteLine("ConnectionName = " + sp.ConnectionName);

            // Display the maximum number of connections allowed on this
            // ServicePoint instance.
            Console.WriteLine("ConnectionLimit = " + sp.ConnectionLimit);

            // Display the number of connections associated with this
            // ServicePoint instance.
            Console.WriteLine("CurrentConnections = " + sp.CurrentConnections);

            if (sp.Certificate == null)
                Console.WriteLine("Certificate = (null)");
            else
                Console.WriteLine("Certificate = " + sp.Certificate.ToString());

            if (sp.ClientCertificate == null)
                Console.WriteLine("ClientCertificate = (null)");
            else
                Console. WriteLine("ClientCertificate = " + sp.ClientCertificate.ToString());

            Console.WriteLine("ProtocolVersion = " + sp.ProtocolVersion.ToString());
            Console.WriteLine("SupportsPipelining = " + sp.SupportsPipelining);

            Console.WriteLine("UseNagleAlgorithm = " + sp.UseNagleAlgorithm.ToString());
            Console.WriteLine("Expect 100-continue = " + sp.Expect100Continue.ToString());
        }

        private static void makeWebRequest(int hashCode, string Uri)
        {
            HttpWebResponse res = null;

            // Make sure that the idle time has elapsed, so that a new
            // ServicePoint instance is created.
            Console.WriteLine("Sleeping for 2 sec.");
            Thread.Sleep(2000);
            try
            {
                // Create a request to the passed URI.
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(Uri);

                Console.WriteLine("\nConnecting to " + Uri + " ............");

                // Get the response object.
                res = (HttpWebResponse)req.GetResponse();
                Console.WriteLine("Connected.\n");

                ServicePoint currentServicePoint = req.ServicePoint;

                // Display new service point properties.
                int currentHashCode = currentServicePoint.GetHashCode();

                Console.WriteLine("New service point hashcode: " + currentHashCode);
                Console.WriteLine("New service point max idle time: " + currentServicePoint.MaxIdleTime);
                Console.WriteLine("New service point is idle since " + currentServicePoint.IdleSince );

                // Check that a new ServicePoint instance has been created.
                if (hashCode == currentHashCode)
                    Console.WriteLine("Service point reused.");
                else
                    Console.WriteLine("A new service point created.") ;
            }
            catch (Exception e)
            {
                Console.WriteLine("Source : " + e.Source);
                Console.WriteLine("Message : " + e.Message);
            }
            finally
            {
                if (res != null)
                    res.Close();
            }
        }

        // Show the user how to use this program when wrong inputs are entered.
        private static void showUsage()
        {
            Console.WriteLine("Enter the proxy name as follows:");
            Console.WriteLine("\tcs_servicepoint proxyName");
        }

        public static void Main(string[] args)
        {
            int port = 80;

            // Define a regular expression to parse the user's input.
            // This is a security check. It allows only
            // alphanumeric input strings between 2 to 40 characters long.
            Regex rex = new Regex(@"^[a-zA-Z]\w{1,39}$");

            if (args.Length < 1)
            {
                showUsage();
                return;
            }
            string proxy = args[0];

            if (!(rex.Match(proxy)).Success)
            {
                Console.WriteLine("Input string format not allowed.");
                return;
            }
            string proxyAdd = "http://" + proxy + ":" + port;

            // Create a proxy object.
            WebProxy DefaultProxy = new WebProxy(proxyAdd, true);

            // Set the proxy that all HttpWebRequest instances use.
            WebRequest.DefaultWebProxy = DefaultProxy;

            // Get the base interface for proxy access for the
            // WebRequest-based classes.
            IWebProxy Iproxy = WebRequest.DefaultWebProxy;

            // Set the maximum number of ServicePoint instances to
            // maintain. If a ServicePoint instance for that host already
            // exists when your application requests a connection to
            // an Internet resource, the ServicePointManager object
            // returns this existing ServicePoint instance. If none exists
            // for that host, it creates a new ServicePoint instance.
            ServicePointManager.MaxServicePoints = 4;

            // Set the maximum idle time of a ServicePoint instance to 10 seconds.
            // After the idle time expires, the ServicePoint object is eligible for
            // garbage collection and cannot be used by the ServicePointManager object.
            ServicePointManager.MaxServicePointIdleTime = 10000;

            ServicePointManager.UseNagleAlgorithm = true;
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.CheckCertificateRevocationList = true;
            ServicePointManager.DefaultConnectionLimit = ServicePointManager.DefaultPersistentConnectionLimit;
            // Create the Uri object for the resource you want to access.
            Uri MS = new Uri("http://msdn.microsoft.com/");

            // Use the FindServicePoint method to find an existing
            // ServicePoint object or to create a new one.
            ServicePoint servicePoint = ServicePointManager.FindServicePoint(MS, Iproxy);

            ShowProperties(servicePoint);

            int hashCode = servicePoint.GetHashCode();

            Console.WriteLine("Service point hashcode: " + hashCode);

            // Make a request with the same scheme identifier and host fragment
            // used to create the previous ServicePoint object.
            makeWebRequest(hashCode, "http://msdn.microsoft.com/library/");
        }
    }
}

' This example shows how to use the ServicePoint and ServicePointManager classes.
' The ServicePointManager class uses the ServicePoint class to manage connections
' to a remote host. The networking classes reuse service points for all 
' requests to a given URI. In fact, the same ServicePoint object 
' is used to issue requests to Internet resources identified by the same
' scheme identifier (for example,  HTTP) and host fragment (for example,  www.contoso.com).  
' Reusing service points in this way can help improve application  performance.

Imports System.Net
Imports System.Threading
Imports System.Text.RegularExpressions

Namespace Mssc.Services.ConnectionManagement
    Module M_TestServicePoint

        Class TestServicePoint
            Private Shared Sub ShowProperties(ByVal sp As ServicePoint)

                Console.WriteLine("Done calling FindServicePoint")

                ' Display the ServicePoint Internet resource address.
                Console.WriteLine(("Address = " + sp.Address.ToString()))

                ' Display the date and time that the ServicePoint was last 
                ' connected to a host.
                Console.WriteLine(("IdleSince = " + sp.IdleSince.ToString()))


                ' Display the maximum length of time that the ServicePoint instance 
                ' is allowed to maintain an idle connection to an Internet  
                ' resource before it is recycled for use in another connection.
                Console.WriteLine(("MaxIdleTime = " + sp.MaxIdleTime.ToString()))

                Console.WriteLine(("ConnectionName = " + sp.ConnectionName))

                ' Display the maximum number of connections allowed on this 
                ' ServicePoint instance.
                Console.WriteLine(("ConnectionLimit = " + sp.ConnectionLimit.ToString()))

                ' Display the number of connections associated with this 
                ' ServicePoint instance.
                Console.WriteLine(("CurrentConnections = " + sp.CurrentConnections.ToString()))

                If sp.Certificate Is Nothing Then
                    Console.WriteLine("Certificate = (null)")
                Else
                    Console.WriteLine(("Certificate = " + sp.Certificate.ToString()))
                End If

                If sp.ClientCertificate Is Nothing Then
                    Console.WriteLine("ClientCertificate = (null)")
                Else
                    Console.WriteLine(("ClientCertificate = " + sp.ClientCertificate.ToString()))
                End If

                Console.WriteLine("ProtocolVersion = " + sp.ProtocolVersion.ToString())
                Console.WriteLine(("SupportsPipelining = " + sp.SupportsPipelining.ToString()))


                Console.WriteLine("UseNagleAlgorithm = " + sp.UseNagleAlgorithm.ToString())
                Console.WriteLine("Expect 100-continue = " + sp.Expect100Continue.ToString())
            End Sub





            Private Shared Sub makeWebRequest(ByVal hashCode As Integer, ByVal Uri As String)
                Dim res As HttpWebResponse = Nothing

                ' Make sure that the idle time has elapsed, so that a new 
                ' ServicePoint instance is created.
                Console.WriteLine("Sleeping for 2 sec.")
                Thread.Sleep(2000)

                Try
                    ' Create a request to the passed URI.
                    Dim req As HttpWebRequest = CType(WebRequest.Create(Uri), HttpWebRequest)
                    Console.WriteLine((ControlChars.Lf + "Connecting to " + Uri + " ............"))

                    ' Get the response object.
                    res = CType(req.GetResponse(), HttpWebResponse)
                    Console.WriteLine("Connected." + ControlChars.Lf)
                    Dim currentServicePoint As ServicePoint = req.ServicePoint

                    ' Display new service point properties.
                    Dim currentHashCode As Integer = currentServicePoint.GetHashCode()
                    Console.WriteLine(("New service point hashcode: " + currentHashCode.ToString()))
                    Console.WriteLine(("New service point max idle time: " + currentServicePoint.MaxIdleTime.ToString()))
                    Console.WriteLine(("New service point is idle since " + currentServicePoint.IdleSince.ToString()))

                    ' Check that a new ServicePoint instance has been created.
                    If hashCode = currentHashCode Then
                        Console.WriteLine("Service point reused.")
                    Else
                        Console.WriteLine("A new service point created.")
                    End If
                Catch e As Exception
                    Console.WriteLine(("Source : " + e.Source))
                    Console.WriteLine(("Message : " + e.Message))
                Finally
                    If Not (res Is Nothing) Then
                        res.Close()
                    End If
                End Try
            End Sub


            ' Show the user how to use this program when wrong inputs are entered.
            Private Shared Sub showUsage()
                Console.WriteLine("Enter the proxy name as follows:")
                Console.WriteLine(ControlChars.Tab + "vb_servicepoint proxyName")
            End Sub

            ' This is the program entry point. It allows the user to enter 
            ' a server name that is used to locate its current homepage.
            Public Shared Sub Main(ByVal args() As String)
                Dim proxy As String = Nothing
                Dim port As Integer = 80

                ' Define a regular expression to parse the user's input.
                ' This is a security check. It allows only
                ' alphanumeric input strings between 2 to 40 characters long.
                Dim rex As New Regex("^[a-zA-Z]\w{1,39}$")

                If args.Length = 0 Then
                    ' Show how to use this program.
                    showUsage()
                    Return
                End If

                proxy = args(0)
                If (Not (rex.Match(proxy)).Success) Then
                    Console.WriteLine("Input string format not allowed.")
                    Return
                End If

                ' Create a proxy object.  
                Dim proxyAdd As String
                proxyAdd = "http://" + proxy + ":" + port.ToString()


                Dim DefaultProxy As New WebProxy(proxyAdd, True)

                ' Set the proxy that all HttpWebRequest instances use.
                WebRequest.DefaultWebProxy = DefaultProxy


                ' Get the base interface for proxy access for the 
                ' WebRequest-based classes.
                Dim Iproxy As IWebProxy = WebRequest.DefaultWebProxy

                ' Set the maximum number of ServicePoint instances to maintain.
                ' Note that, if a ServicePoint instance for that host already 
                ' exists when your application requests a connection to
                ' an Internet resource, the ServicePointManager object
                ' returns this existing ServicePoint. If none exists 
                ' for that host, it creates a new ServicePoint instance.
                ServicePointManager.MaxServicePoints = 4

                ' Set the maximum idle time of a ServicePoint instance to 10 seconds.
                ' After the idle time expires, the ServicePoint object is eligible for
                ' garbage collection and cannot be used by the ServicePointManager.
                ServicePointManager.MaxServicePointIdleTime = 10000


                ServicePointManager.UseNagleAlgorithm = True
                ServicePointManager.Expect100Continue = True
                ServicePointManager.CheckCertificateRevocationList = True
                ServicePointManager.DefaultConnectionLimit = _
                    ServicePointManager.DefaultPersistentConnectionLimit
                ' Create the Uri object for the resource you want to access.
                Dim MS As New Uri("http://msdn.microsoft.com/")

                ' Use the FindServicePoint method to find an existing 
                ' ServicePoint object or to create a new one.   
                Dim servicePoint As ServicePoint = ServicePointManager.FindServicePoint(MS, Iproxy)
                ShowProperties(servicePoint)
                Dim hashCode As Integer = servicePoint.GetHashCode()
                Console.WriteLine(("Service point hashcode: " + hashCode.ToString()))

                ' Make a request with the same scheme identifier and host fragment
                ' used to create the previous ServicePoint object.
                makeWebRequest(hashCode, "http://msdn.microsoft.com/library/")

            End Sub


        End Class

    End Module
End Namespace

注解

该 ServicePoint 类基于在资源的统一资源标识符（URI）中传递的主机信息处理与 Internet 资源的连接。 与资源的初始连接确定对象维护的信息 ServicePoint ，然后由该资源的所有后续请求共享。

ServicePoint 对象由 ServicePointManager 类管理，并在必要时由 ServicePointManager.FindServicePoint 该方法创建。 ServicePoint 对象永远不会直接创建，但始终由 ServicePointManager 类创建和管理。 属性设置ServicePointManager.MaxServicePoints可创建的最大对象数ServicePoint。

每个 ServicePoint 对象保持与 Internet 资源的连接，直到其空闲时间超过属性中指定的 MaxIdleTime 时间。 如果某个 ServicePoint 值超过该值 MaxIdleTime ，则可以将其回收到另一个连接。 MaxIdleTime默认值由ServicePointManager.MaxServicePointIdleTime属性设置。

ConnectionLeaseTimeout当属性设置为除 -1 以外的值，并在指定的时间过后关闭活动ServicePoint连接后，它会为下一个请求提供服务。 这对于不需要无限期打开的活动连接的应用程序非常有用，因为它们在默认情况下处于默认状态。