Springboot整合Netty详解，与客户端的通信协议为websoket

  <!--netty-->
  <dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.6.Final</version>
  </dependency>

public class WSServer {
    private NioEventLoopGroup boss; //负责接收客户端过来的线程模型
    private NioEventLoopGroup worker;//负责数据读写的线程模型
    private ServerBootstrap bootstrap;//Netty服务器启动引导类
    private ChannelFuture channelFuture;//一个执行异步操作后，将来可能会发生事件的状态

    private static class SingletonInstance{
        static final WSServer wsServer = new WSServer();
    }

    public static WSServer getInstance(){
        return SingletonInstance.wsServer;
    }

    private WSServer(){
        boss = new NioEventLoopGroup();
        worker = new NioEventLoopGroup();
        bootstrap = new ServerBootstrap();

        bootstrap.group(boss,worker)//指定服务器的线程模型
                .channel(NioServerSocketChannel.class)//指定IO操作的模型
                .option(ChannelOption.SO_BACKLOG,10240)//客户端可连接队列大小
                .option(ChannelOption.SO_REUSEADDR,true)//允许重复使用地址和端口
                .childOption(ChannelOption.SO_KEEPALIVE,true)//保活开关
                .childOption(ChannelOption.TCP_NODELAY,true)//是否禁用Nagle算法，true表示禁用，即消息来了立即发送，false表示开启，即攒够一定数据了然后批量发送
                .childHandler(new MyChannelInitializer());//初始化处理器
    }

    public void start(){
        this.channelFuture = bootstrap.bind(8808);
        System.out.println("WSServer启动成功...");
    }
}

public class MyChannelInitializer extends ChannelInitializer {
    @Override
    protected void initChannel(Channel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        // websocket 基于http协议，所以要有http编解码器
        pipeline.addLast(new HttpServerCodec());
        // 对写大数据流的支持
        pipeline.addLast(new ChunkedWriteHandler());
        // 对httpMessage进行聚合，聚合成FullHttpRequest或FullHttpResponse
        pipeline.addLast(new HttpObjectAggregator(1024*64));
        //指定客户端连接过来时，访问的路由以：ws开头
        pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));

        //心跳检测
        pipeline.addLast(new IdleStateHandler(8,10,15));//写这一行之后，会触发ChannelInboundHandlerAdapter中的userEventTriggered方法，也就是第四步中定义的心跳处理器
        pipeline.addLast(new HeartBeatHandler());

        //自定义处理器
        pipeline.addLast(new CustomChatHandler());
    }
}