Question

我正在尝试在Visual Basic中创建TCP / IP侦听器。监听器需要能够处理在任何给定时间连接的许多不同客户端。我开发的代码似乎使用

    socket.BeginAcceptSocket()

方法。从我见过的大多数示例中，我都会侦听新连接，接收它，处理它，停止接受该套接字，处理数据，然后关闭连接。我生成的线程是为了正确处理数据的接收和处理而处理的事情。

但是，出于某种原因，我似乎得到了为BeginAcceptSocket方法创建的无限数量的线程。这导致我的计算机速度变慢，最终只是锁定，我开始丢失来自客户端等的数据等。我会在这里发布我的代码，但基本上有一些显而易见的我在这里做错了吗？我安静地花了一些时间搜索并试图调试它，我很困惑。

Imports System.Net.Sockets, System.Threading, System.IO, System.Net

Imports System.Text
Imports System.Data, System.Data.SqlClient

Module Module1
'The Tcp listener listening on port 2012
Dim listener As New TcpListener(IPAddress.Any, 2012)

'Signal for when to start listening on a new socket for a client
Private clientConnected As New ManualResetEvent(False)

'The threads being used for the processing
Private listenThread, test As Thread

Sub Main()
    listener.Start()
    listenThread = New Thread(AddressOf doListen)

    listenThread.IsBackground = True
    listenThread.Start()

    Do
        Select Case Console.ReadLine().ToLower
            Case "exit"
                Exit Do
        End Select
    Loop
End Sub

Sub message(ByVal msg As String)
    msg.Trim()
    Console.WriteLine(">> " + msg)
End Sub

Sub doListen()
    'Reset the signal
    clientConnected.Reset()
    Do
        'Start listening for new Sockets, upon a new socket create a new thread @ AcceptClients
        listener.BeginAcceptSocket(New AsyncCallback(AddressOf AcceptClients), listener)
        'Wait for the new socket to be handled
        clientConnected.WaitOne()
        'Reset the flag and then repeat
        clientConnected.Reset()
    Loop
End Sub
Sub AcceptClients(ar As IAsyncResult)
    'Get the listener that handles the request
    Dim listen As TcpListener = CType(ar.AsyncState, TcpListener)
    'Create a new socket and end the listening on that socket
    Dim clientSocket As Socket = listen.EndAcceptSocket(ar)

    'Notify the main thread that it is ready to listen for new connections
    clientConnected.Set()

    'Define variables used for lisetning and parsing messages
    Dim byteRec(1024) As Byte
    Dim message As String = Nothing
    Dim N, C As Integer
    Dim lengthFound As Boolean = False
    Dim finished As Boolean = False

    Do
        Try
            Dim intBytes As Int32 = clientSocket.Receive(byteRec, 0, clientSocket.Available,
                        SocketFlags.None)
            message = ASCIIEncoding.ASCII.GetString(byteRec, 0, intBytes)

            If intBytes > 0 Then ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf printMsg), message)

            'If message.Contains(Chr(1)) And Not lengthFound Then
            '    'Call method to return the total number of messages in the group
            '    N = getNumber(message, message.IndexOf(Chr(1)) + 1)
            '    lengthFound = True
            'End If
            'C = getCountOfMessages(message)
            'If getCountOfMessages(message) = N And lengthFound Then
            '    finished = True
            '    Exit Do
            'End If

            While intBytes > 0 And Not finished
                intBytes = clientSocket.Receive(byteRec, 0, clientSocket.Available, SocketFlags.None)
                message = ASCIIEncoding.ASCII.GetString(byteRec, 0, intBytes)

                'Somehow need to look for the number of STX's and increment the counter by each number
                'C = getCountOfMessages(message)
                'If message.Contains(Chr(1)) And Not lengthFound Then
                '    'Call method to return the total number of messages in the group
                '    N = getNumber(message, message.IndexOf(Chr(1)) + 1)
                '    lengthFound = True
                'End If
                'If getCountOfMessages(message) = N And lengthFound Then
                '    finished = True
                '    Exit Do
                'End If

            End While
        Catch ex As Exception

        End Try

    Loop
    ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf printMsg), message)
    clientSocket.Close()
    clientSocket.Dispose()

End Sub
'Method to return the total number of messages RECEIVED from a group
Function getCountOfMessages(ByVal message As String)
    Dim C As Integer = 0
    C = message.Split(Chr(2)).Count - 1
    Return C
End Function
'Method to return the total number of messages in a group. Paramters are the total message string and the index of the SOH char
Function getNumber(ByVal message As String, ByVal index As Integer)
    Dim N As Integer = 0
    'Create a loop to start at the SOH and convert all data between SOH and ETX to N as an integer and return it 
    Dim S As Boolean = True
    Dim temp As String = ""
    While S
        Select Case message(index)
            Case Chr(3)
                'End of message is found, exit loop
                S = False
            Case Else
                'Add the data between the SOH and ETX to a string. Once finished convert the data to an int
                '       The reason I think this is neccessary would be in case we decide to have more than 9 messages, aka 2 or more digit numbers. like 10 or 300 etc..
                temp = temp + message(index)
        End Select
        index = index + 1
    End While
    N = Convert.ToInt32(temp)
    Return N
End Function
'This method will be used to reorder, parse and delimt the messages then add them into the SQL database
Sub printMsg(ByVal msg As Object)

    Dim dataStr As String = ""

    Debug.Print(msg & vbCrLf)
End Sub
End Module

非常感谢任何帮助。

Answer 1

有多少客户端可以并行发送数据？什么类型的数据由客户发送？收到客户端发送后，您是否运行了一些进程？只是确保。

强大的Visual Basic TCP / IP侦听器问题

1 个答案: