netty学习：基于WebSocket协议开发服务端及客户端，实现双向通信

学习过程中有参考Redisson和RocketMq对于netty的使用

一、服务端

1、启动类

    @Autowired
    private WebsocketProperties properties;
    @Autowired
    private WebSocketChannelInitializer webSocketChannelInitializer;

    NioEventLoopGroup bossGroup = new NioEventLoopGroup();
    NioEventLoopGroup workerGroup = new NioEventLoopGroup();

    public void start() throws InterruptedException {
        prepareExecutorService();
        ServerBootstrap serverBootstrap = new ServerBootstrap();
        serverBootstrap.group(bossGroup, workerGroup)
                .channel(NioServerSocketChannel.class)
                .option(ChannelOption.SO_BACKLOG, 1024)
                .childOption(ChannelOption.TCP_NODELAY, true)
                .childOption(ChannelOption.SO_KEEPALIVE, true)
                .childHandler(webSocketChannelInitializer);

        Channel channel = serverBootstrap.bind(properties.getPort()).sync().channel();
        log.info("Websocket server run at port: " + properties.getPort());
        channel.closeFuture().sync();
    }

2、实现ChannelInitializer(暂时未考虑ssl)

    @Autowired
    private WebsocketProperties properties;
    @Autowired
    private HttpRequestHandler httpRequestHandler;
    @Autowired
    private TextWebSocketFrameHandler textWebSocketFrameHandler;

    @Override
    protected void initChannel(SocketChannel channel) throws Exception {
        ChannelPipeline pipeline = channel.pipeline();
        SslContext sslContext = configureSslContext();
        if (sslContext != null) {
            pipeline.addLast(sslContext.newHandler(channel.alloc()));
        }
        pipeline
                .addLast(new WebSocketIdleStateHandler())
                .addLast(new HttpServerCodec())
                .addLast(new HttpObjectAggregator(65536))
                .addLast(httpRequestHandler)
                .addLast(PingWebSocketFrameHandler.INSTANCE)
                .addLast(textWebSocketFrameHandler)
                .addLast(CloseWebSocketFrameHandler.INSTANCE);
    }

 配置的空闲检测为读15秒钟，客户端心跳请求