1.新建MessageBean消息类型类，也可以不用，看自己需要

public enum MsgType { STATUS_CONNECT_ERROR, STATUS_CONNECT_SUCCESS, STATUS_CONNECT_CLOSED, STATUC_CONNECT_RECONNECT }public class MessageBean
{/*** 消息类型*/private MsgType type;/*** 消息数据*/private Object msg;public MessageBean(MsgType type,Object msg){this.type = type;this.msg = msg;}public Object getMsg(){return msg;}public void setMsg(Object msg){this.msg = msg;}public void setType(MsgType type){this.type = type;}public MsgType getType(){return type;}public override string ToString(){return "MsgBean{" +"type=" + type +", msg=" + msg +'}';}
}

2.新建DotNettyClientHandler类，用于接收服务端消息

public class DotNettyClientHandler : FlowControlHandler
{/// <param name="ctx"></param>/// <param name="msg"></param>private DotNettyListener listener;private static String strMsg; public DotNettyClientHandler(DotNettyListener listener){this.listener = listener;}public override void ChannelActive(IChannelHandlerContext context){Console.WriteLine("==================ChannelActive======================");if (null != listener){listener.onServiceStatusConnectChanged(new MessageBean(MsgType.STATUS_CONNECT_SUCCESS, null));}}public override void ChannelInactive(IChannelHandlerContext context){base.ChannelInactive(context);//掉线了Console.WriteLine("===============ChannelInactive==============");if (null != listener){listener.onServiceStatusConnectChanged(new MessageBean(MsgType.STATUS_CONNECT_CLOSED, null));}DotNettyClient.getInstance(listener).start();}public override void ChannelRead(IChannelHandlerContext context, object msg){Console.WriteLine("===============ChannelRead==============");IByteBuffer byteBuffer = msg as IByteBuffer;strMsg += byteBuffer.ToString(Encoding.UTF8);if (byteBuffer != null){Console.WriteLine("byteBuffer:" + strMsg);if (strMsg.StartsWith("{") && strMsg.EndsWith("}")){listener.onMessageResponse(strMsg);strMsg = null;}}else {Console.WriteLine("---------null---------- ");}//context.WriteAsync(msg);}public override void ChannelReadComplete(IChannelHandlerContext context){Console.WriteLine("===============ChannelReadComplete==============");context.Flush();}public override void UserEventTriggered(IChannelHandlerContext context, object evt){Console.WriteLine("----------------UserEventTriggered----------------");base.UserEventTriggered(context, evt);if (evt is IdleStateEvent){var e = evt as IdleStateEvent;switch (e.State){//长期没收到服务器推送数据/**case IdleState.ReaderIdle:{//可以重新连接if (!context.Channel.Active)context.ConnectAsync(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9997));}break;//长期未向服务器发送数据case IdleState.WriterIdle:{//发送心跳包byte[] messageBytes = Encoding.UTF8.GetBytes("heartbeat");context.WriteAndFlushAsync(messageBytes);}break;**///Allcase IdleState.AllIdle:{//发送心跳包}break;}}}public override void ExceptionCaught(IChannelHandlerContext context, Exception exception){Console.WriteLine("===============ExceptionCaught==============");Console.WriteLine(exception);context.CloseAsync();if (null != listener){listener.onServiceStatusConnectChanged(new MessageBean(MsgType.STATUS_CONNECT_ERROR, exception.Message));}}
}

3.新建DotNettyClient类，管理DotNetty连接，消息发送

public interface DotNettyListener
{/*** 当接收到系统消息*/void onMessageResponse(Object msg);/*** 当连接状态发生变化时调用*/void onServiceStatusConnectChanged(MessageBean msg);
}
public class DotNettyClient
{#region Instancepublic IChannel clientChannel;public String ip = "127.0.0.1";//ippublic int port = 9997;//端口private DotNettyListener listener;//写的接口用来接收服务端返回的值private static DotNettyClient instance;public static DotNettyClient getInstance(DotNettyListener listener) {if (instance == null) {instance = new DotNettyClient();}instance.setListener(listener);return instance;}private DotNettyClient(){ }#endregionprivate ManualResetEvent ClosingArrivedEvent = new ManualResetEvent(false);public void start(){try{Task.Run(() => runClientAsync(ip,port));}catch (Exception exception){Console.WriteLine(exception.StackTrace);}}public async Task runClientAsync(String ip,int host){var group = new MultithreadEventLoopGroup();X509Certificate2 cert = null;string targetHost = null;try{var bootstrap = new Bootstrap();bootstrap.Group(group).Channel<TcpSocketChannel>().Option(ChannelOption.TcpNodelay, true)//.Option(ChannelOption.ConnectTimeout, new TimeSpan(0, 0, 0, 0, args.ConnectTimeout)).Handler(new ActionChannelInitializer<ISocketChannel>(channel =>{IChannelPipeline pipeline = channel.Pipeline;pipeline.AddLast(new StringEncoder(Encoding.UTF8));//pipeline.AddLast(new StringDecoder(Encoding.UTF8));pipeline.AddLast(new IdleStateHandler(0, 0, 100));pipeline.AddLast(new DotNettyClientHandler(listener));//定义Handler类及名称                }));clientChannel = await bootstrap.ConnectAsync(ip,port);ClosingArrivedEvent.Reset();ClosingArrivedEvent.WaitOne();await clientChannel.CloseAsync();}catch (Exception exp){//MainWindow.SetText("Client connection failed");Console.WriteLine(exp.ToString());Console.WriteLine(exp.StackTrace);}finally{//await group.ShutdownGracefullyAsync(TimeSpan.FromMilliseconds(100), TimeSpan.FromSeconds(1));reConnectServer();}}//断线重连private void reConnectServer(){Console.WriteLine("=================reConnectServer===================");if (null != listener) {listener.onServiceStatusConnectChanged(new MessageBean(MsgType.STATUC_CONNECT_RECONNECT, null));}try{Thread.Sleep(5000);start();}catch (Exception e){}}public bool SendMessage(string message){if (clientChannel != null && clientChannel.Open){clientChannel.WriteAndFlushAsync(message);Console.WriteLine("Sent message to server: " + message);return true;}return false;}public void disconnect() {Console.WriteLine("============disconnect==============");//await channel.CloseAsync();clientChannel.CloseAsync();}public void setListener(DotNettyListener listener){this.listener = listener;}
}

4.使用DotNetty

public partial class Form1 : Form, DotNettyListener
{public Form1(){InitializeComponent();}public void onMessageResponse(object msg){Console.WriteLine(msg);}public void onServiceStatusConnectChanged(MessageBean msg){Console.WriteLine("type = "+msg.getType()+",msg = "+msg.getMsg());}private void simpleButton1_Click(object sender, EventArgs e){DotNettyClient client = DotNettyClient.getInstance(this);client.start();Thread.Sleep(5000);client.SendMessage("12345");}
}