vb.net tcp 服务器举例

在VB.NET中，创建TCP服务器的一个基本例子通常是使用`TcpListener`类。以下是简单的步骤和代码示例：

Imports System.Net
Imports System.Net.Sockets

Public Class TcpServer
    Private Sub StartServer()
        ' 创建一个监听器，绑定到特定端口
        Dim listener As New TcpListener(IPAddress.Any, 8080)

        ' 开始监听连接请求
        listener.Start()

        Console.WriteLine("TCP Server started on port " & listener.LocalEndpoint.Port)

        ' 当有新的客户端连接时...
        While True
            ' 获取一个新的网络流
            Dim client As TcpClient = listener.AcceptTcpClient()

            ' 创建一个线程来处理每个客户端连接
            Dim clientThread As New Thread(New ParameterizedThreadStart(AddressOf HandleClient))
            clientThread.Start(client)
        End While
    End Sub

    ' 客户端处理方法
    Private Shared Sub HandleClient(ByVal client As TcpClient)
        Try
            ' 创建一个网络流来读取和写入数据
            Dim networkStream As NetworkStream = client.GetStream()
            Dim buffer(1024) As Byte
            Dim receivedData As String = ""

            ' 接收客户端发送的数据
            Do
                Dim bytesRead As Integer = networkStream.Read(buffer, 0, buffer.Length)
                If bytesRead > 0 Then
                    receivedData += Encoding.ASCII.GetString(buffer, 0, bytesRead)
                Else
                    Exit Do
                End If
            Loop

            Console.WriteLine("Received from client: " & receivedData)

            ' 发送响应给客户端
            networkStream.Write(Encoding.ASCII.GetBytes("Hello, client!"), 0, "Hello, client!".Length)

            ' 关闭连接
            client.Close()
        Catch ex As Exception
            Console.WriteLine("Error: " & ex.Message)
        Finally
            ' 确保清理资源
            client.Close()
        End Try
    End Sub

    Public Shared Sub Main()
        ' 启动服务器
        Dim server As New TcpServer()
        Threading.Thread.CurrentThread.IsBackground = True
        server.StartServer()
    End Sub
End Class

这段代码首先启动了一个TCP服务器监听8080端口。每当有新客户端连接时，它会在单独的线程上创建一个`HandleClient`方法来处理接收到的消息，向客户端发送响应，并关闭连接。