Question

我正在做一个项目，我使用socket连接到USSD服务器。该项目是一个实时和24小时运行的调度程序。

以下是我的BeginReceive()和EndReceive()

的代码

Public Sub Receive(ByVal client As Socket)

    Dim state As New StateObject
    state.workSocket = client

    Try

        If m_clientSocket.Connected Then

             client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, New AsyncCallback(AddressOf ReceiveCallback), state)
         Else
             Connect()
         End If

    Catch se As SocketException

        logstr = se.Message
        write_log(logstr, "Receive", "Receive")

    End Try

End Sub

Public Sub ReceiveCallback(ByVal ar As IAsyncResult)

    Dim state       As StateObject = CType(ar.AsyncState, StateObject)
    Dim client      As Socket      = state.workSocket
    Dim receiveData As String      = ""
    Dim sendData    As String      = ""

    Dim bytesRead   As Integer     = client.EndReceive(ar)

    If bytesRead > 0 Then

        state.sb.Append(System.Text.Encoding.ASCII.GetString(state.buffer, 0, bytesRead))

        client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, New AsyncCallback(AddressOf ReceiveCallback), state)      

        receiveData = state.sb.ToString()

        Me.lsBulk.Items.Insert(0, receiveData)
        sendData = getReply(receiveData)
        write_log(Now.ToString & " : " & receiveData & vbCrLf, "bytesRead", "bytesRead")

        Try

            Dim objData As [Object] = sendData
            Dim byData As Byte() = System.Text.Encoding.ASCII.GetBytes(objData.ToString())
            If m_clientSocket IsNot Nothing Then
                m_clientSocket.Send(byData)
            End If

            write_log(Now.ToString & " : " & sendData & vbCrLf, "sendData", "sendData")

        Catch se As SocketException

            logstr = se.Message
            write_log(logstr, "WaitForData", "waitfordata")

        End Try

    Else

        receiveData = state.sb.ToString()

        If receiveData <> "" Then

            write_log(Now.ToString & " : " & receiveData & vbCrLf, "receiveData2", "receiveData2")

        End If

    End If

End Sub

问题是这个程序占用了我很多的记忆。第一次运行后它需要3.5GB然后一小时后它需要4.5GB，依此类推，直到或除非我们重启它。它正在成为服务器的一大麻烦，因为它在内存中分配了大量空间。

我无法理解我必须清除缓冲区以释放系统内存。每次写入数据库时，缓冲区中的数据都不需要保留。

我想提一下，每次缓冲区大小为10024。

Answer 1

据我所知，问题是你不断在你的StringBuilder实例中附加文本而从不发布它。你的缓冲区很好，因为它只是重新使用已经分配的内存。

您只需设置sb.Length = 0即可清除StringBuilder。在我看来，这是一个奇怪的API，我觉得应该有.Clear()方法。

当我读完你的代码时，我不确定为什么你有一个StringBuilder实例。它在其他地方做了什么？ StateObject的定义是什么？

如何在BeginReceive（）和EndReceive（）函数之后清除系统内存？

1 个答案: