我正在尝试在 Visual Basic 中创建 TCP/IP 侦听器。侦听器需要能够在任何给定时间处理许多不同的客户端连接。我开发的代码似乎可以使用
socket.BeginAcceptSocket()
方法。从我见过的大多数示例中，我侦听一个新连接，接收它，处理它，停止在该套接字上接受，处理数据，然后关闭连接。我为正确处理数据的接收和处理而生成的线程并得到妥善处理。
但是，由于某种原因，我似乎获得了为我的 BeginAcceptSocket 方法创建的无限数量的线程。这会导致我的计算机变慢并最终锁定，并且我开始丢失来自客户端等的数据。我将在下面发布我的代码，但基本上有什么明显的我做错了吗？我花了一些时间安静地四处搜索并尝试调试它，但我很困惑。
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
任何帮助是极大的赞赏。