Documenting source code.

@@ -17,7 +17,7 @@ public class CustomerHandleInitializer extends ChannelInitializer<Channel> {
     @Override
     protected void initChannel(Channel ch) throws Exception {
         ch.pipeline()
-                //10 秒没发送消息
+                //10 秒没发送消息 将IdleStateHandler 添加到 ChannelPipeline 中
                 .addLast(new IdleStateHandler(0, 10, 0))
                 .addLast(new HeartbeatEncode())
                 .addLast(new EchoClientHandle())

@@ -64,6 +64,7 @@ public class HeartBeatSimpleHandle extends SimpleChannelInboundHandler<CustomPro
     protected void channelRead0(ChannelHandlerContext ctx, CustomProtocol customProtocol) throws Exception {
         LOGGER.info("收到customProtocol={}", customProtocol);
 
+        //保存客户端与 Channel 之间的关系
         NettySocketHolder.put(customProtocol.getId(),(NioSocketChannel)ctx.channel()) ;
     }
 }