通过nioSocketChannel.pipeline()的addLast添加入站处理器，如果有多个必须显示的唤醒下一个入站处理器，否则执行链中间会断掉。

protected void initChannel(NioSocketChannel nioSocketChannel) throws Exception {log.debug(nioSocketChannel.toString());//添加各种处理器nioSocketChannel.pipeline().addLast(new LoggingHandler());nioSocketChannel.pipeline().addLast(new StringDecoder());//字符串解析器nioSocketChannel.pipeline().addLast(new ChannelInboundHandlerAdapter() {@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {log.debug("msg 1 : {}",msg);//这里未调用唤醒下一个处理器}});nioSocketChannel.pipeline().addLast(new ChannelInboundHandlerAdapter(){@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {log.debug("msg 1 : {}",msg);super.channelRead(ctx, msg);}});
}

执行结果：

 解决方法：

super.channelRead(ctx, msg);源码：

该函数调用的是：

public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {ctx.fireChannelRead(msg);
}

进一步跟踪调用：

public ChannelHandlerContext fireChannelRead(final Object msg) {//找到下一个ｈａｎｄｌｅｒ并执行invokeChannelRead(findContextInbound(MASK_CHANNEL_READ), msg);return this;
}

static void invokeChannelRead(final AbstractChannelHandlerContext next, Object msg) {final Object m = next.pipeline.touch(ObjectUtil.checkNotNull(msg, "msg"), next);EventExecutor executor = next.executor();if (executor.inEventLoop()) {next.invokeChannelRead(m);} else {//新启动一个线程，执行新的处理器executor.execute(new Runnable() {@Overridepublic void run() {next.invokeChannelRead(m);}});}
}

附加：入站处理器调用出站后，分别有：

ChannelHandlerContext．writeAndFlush：从当前处理器往前找

nioSocketChannel.writeAndFlush：从最后一个处理依次往前找。

上图执行顺序：

入站1－》入站2－》入站2调用出站－》当前往前找－》出站1

NioSocketChannel　会从后往前找出站处理器，

ChannelHandlerContext：会从当前处理器往前找出战处理器。

                        nioSocketChannel.pipeline().addLast(new ChannelInboundHandlerAdapter() {@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {System.out.println("msg 1 : " + msg);//唤醒下一个handler，同时可以将消息进一步处理super.channelRead(ctx, msg + "我已经被处理过");}});nioSocketChannel.pipeline().addLast(new ChannelOutboundHandlerAdapter() {@Overridepublic void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {System.out.println("调用出战处理器 1");System.out.println(msg.toString());super.write(ctx, msg, promise);}});nioSocketChannel.pipeline().addLast(new ChannelInboundHandlerAdapter() {@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) {//得到消息，是第一个handler处理过后的内容System.out.println("msg 2 : " + msg);//ctx.writeAndFlush(ctx.alloc().buffer().writeBytes("出出出出出".getBytes()));//nioSocketChannel 会从最后一个依次向前找出站处理器nioSocketChannel.writeAndFlush(ctx.alloc().buffer().writeBytes("出出出出出".getBytes()));}});nioSocketChannel.pipeline().addLast(new ChannelOutboundHandlerAdapter() {@Overridepublic void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {System.out.println("调用出战处理器 2");System.out.println(msg.toString());super.write(ctx, msg, promise);}});nioSocketChannel.pipeline().addLast(new ChannelOutboundHandlerAdapter() {@Overridepublic void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {System.out.println("调用出战处理器 3");System.out.println(msg.toString());super.write(ctx, msg, promise);}});}

nioSocketChannel   依次从最后往前调用出站处理器，执行顺序为：  3   2  1