Socket入门笔记 用TcpClient实现一个简易聊天室

Posted 2020-09-30

效果

 

实现思路

使用TcpListener建一个服务器,接收所有客户端发送的消息,然后由服务器再发送到其他客户端

客户端使用TcpClient,发消息给服务器,接收服务器的消息,不和其他客户端直接交互

服务器端

接收客户端

开启一个线程,死循环去接收客户端.接收到之后放到一个集合里,保存起来,以便转发消息用.每个客户端都再开启一个线程,用于接收这个客户端发送的消息.

接收客户端的方法AcceptTcpClient()是阻塞方法,在程序退出释放资源时会引发异常,可以先使用Pending()方法先判断是否有挂起的链接请求,有请求的话再去接收.这样可以避免退出时引发的异常.

这里取每隔1秒接收一次.

/// <summary>
/// 接收客户端
/// </summary>
private void AcceptClient()
{
    try
    {
        while (_isAccept)
        {
            if (_listener.Pending())
            {
                TcpClient client = _listener.AcceptTcpClient();
                IPEndPoint endpoint = client.Client.RemoteEndPoint as IPEndPoint;
                _clients.Add(endpoint.ToString(), client);

                //添加到前端客户端列表
                lbx_Clients.Dispatcher.Invoke(() =>
                {
                    lbx_Clients.Items.Add(endpoint.ToString());
                });

                //接收消息线程
                Thread reciveMessageThread = new Thread(ReciveMessage);
                reciveMessageThread.Start(client);
            }
            else
            {
                Thread.Sleep(1000);
            }
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

接收消息并转发

也是死循环接收,使用Read()方法接收.如果远程主机已关闭连接,Read()将立即返回零字节.此时跳出循环,释放资源,结束此线程.

/// <summary>
/// 接收消息
/// </summary>
/// <param name="obj">TcpClient</param>
private void ReciveMessage(object obj)
{
    TcpClient client = obj as TcpClient;
    IPEndPoint endpoint = null;
    NetworkStream stream = null;

    try
    {
        endpoint = client.Client.RemoteEndPoint as IPEndPoint;
        stream = client.GetStream();

        while (true)
        {
            byte[] data = new byte[1024];
            //如果远程主机已关闭连接,Read将立即返回零字节
            int length = stream.Read(data, 0, data.Length);
            if (length > 0)
            {
                #region if
                string msg = Encoding.UTF8.GetString(data, 0, length);

                //添加到前端消息列表
                lbx_Messages.Dispatcher.Invoke(() =>
                {
                    lbx_Messages.Items.Add(string.Format("{0}:{1}", endpoint.ToString(), msg));
                });

                //发送到其他客户端
                foreach (KeyValuePair<string, TcpClient> kvp in _clients)
                {
                    if (kvp.Value != client)
                    {
                        string writeMsg = string.Format("{0}:{1}", endpoint.ToString(), msg);
                        byte[] writeData = Encoding.UTF8.GetBytes(writeMsg);
                        NetworkStream writeStream = kvp.Value.GetStream();
                        writeStream.Write(writeData, 0, writeData.Length);
                    }
                }
                #endregion
            }
            else
            {
                //客户端断开连接 跳出循环
                break;
            }
        }
    }
    catch (Exception ex)
    {
        //Read是阻塞方法 客户端退出是会引发异常 释放资源 结束此线程
    }
    finally
    {
        //从前端客户端列表移除
        lbx_Clients.Dispatcher.Invoke(() =>
        {
            lbx_Clients.Items.Remove(endpoint.ToString());
        });
        //释放资源
        stream.Dispose();
        _clients.Remove(endpoint.ToString());
        client.Dispose();
    }
}

客户端

接收消息

开启线程,死循环接收服务器发送的消息.如果Read()返回0,说明服务器已关闭.

/// <summary>
/// 接收消息
/// </summary>
private void ReciveMessage()
{
    try
    {
        NetworkStream stream = _client.GetStream();
        while (true)
        {
            byte[] data = new byte[1024];
            int length = stream.Read(data, 0, data.Length);
            if (length > 0)
            {
                string msg = Encoding.UTF8.GetString(data, 0, length);

                //添加到前端消息列表
                lbx_Messages.Dispatcher.Invoke(() =>
                {
                    lbx_Messages.Items.Add(msg);
                });
            }
            else
            {
                MessageBox.Show("服务器已关闭");
                stream.Dispose();
                break;
            }
        }
    }
    catch (Exception ex)
    {
        //Read是阻塞方法 程序退出释放资源是会引发异常 不做处理 线程结束
    }
}

源码下载:

服务器端:SocketServerDemo.zip

客户端:SocketClientDemo.zip