Socket入門筆記 用TcpClient實現一個簡易聊天室

效果

實現思路

使用TcpListener建一個伺服器,接收所有客戶端發送的消息,然後由伺服器再發送到其他客戶端

客戶端使用TcpClient,發消息給伺服器,接收伺服器的消息,不和其他客戶端直接交互

伺服器端

接收客戶端

開啟一個線程,死迴圈去接收客戶端.接收到之後放到一個集合里,保存起來,以便轉發消息用.每個客戶端都再開啟一個線程,用於接收這個客戶端發送的消息.

接收客戶端的方法AcceptTcpClient()是阻塞方法,在程式退出釋放資源時會引發異常,可以先使用Pending()方法先判斷是否有掛起的鏈接請求,有請求的話再去接收.這樣可以避免退出時引發的異常.

這裡取每隔1秒接收一次.

/// <summary>
/// 接收客戶端
/// </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);

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

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

接收消息並轉發

也是死迴圈接收,使用Read()方法接收.如果遠程主機已關閉連接,Read()將立即返回零位元組.此時跳出迴圈,釋放資源,結束此線程.

/// <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];
            //如果遠程主機已關閉連接,Read將立即返回零位元組
            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));
                });

                //發送到其他客戶端
                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
            {
                //客戶端斷開連接 跳出迴圈
                break;
            }
        }
    }
    catch (Exception ex)
    {
        //Read是阻塞方法 客戶端退出是會引發異常 釋放資源 結束此線程
    }
    finally
    {
        //從前端客戶端列表移除
        lbx_Clients.Dispatcher.Invoke(() =>
        {
            lbx_Clients.Items.Remove(endpoint.ToString());
        });
        //釋放資源
        stream.Dispose();
        _clients.Remove(endpoint.ToString());
        client.Dispose();
    }
}

客戶端

接收消息

開啟線程,死迴圈接收伺服器發送的消息.如果Read()返回0,說明伺服器已關閉.

/// <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("伺服器已關閉");
                stream.Dispose();
                break;
            }
        }
    }
    catch (Exception ex)
    {
        //Read是阻塞方法 程式退出釋放資源是會引發異常 不做處理 線程結束
    }
}

源碼下載:

伺服器端:SocketServerDemo.zip

客戶端:SocketClientDemo.zip