DelimiterBasedFrameDecoder/ByteToMessageDecoder

[songj songj]

hi,all:

   I use DelimiterBasedFrameDecoder and ByteToMessageDecoder to decode my message in TCP keepalive.

the server code:

bossGroup = new NioEventLoopGroup(1)
workerGroup = new NioEventLoopGroup
val bootstrap = new ServerBootstrap()
bootstrap.group(bossGroup, workerGroup)
  .channel(classOf[NioServerSocketChannel])
  .option[Integer](ChannelOption.SO_BACKLOG, 10000)
  .option[java.lang.Boolean](ChannelOption.TCP_NODELAY, true)
  .option[java.lang.Boolean](ChannelOption.SO_KEEPALIVE, true)
  .childHandler(new ChannelInitializer[SocketChannel]() {
  override def initChannel(ch: SocketChannel): Unit = {
    val p = ch.pipeline
    p.addLast(sslCtx.newHandler(ch.alloc))

    val delimiter = Unpooled.copiedBuffer(Const.delimiter)
    p.addLast(new DelimiterBasedFrameDecoder(204800, delimiter))

    p.addLast(new ServerMsgDecoder)
    p.addLast(new ServerMsgEncoder)

    p.addLast(new ServerHandler)
  }
})

 

ServerMsgDecoder extends from ByteToMessageDecoder.

But when I run my application, sometimes it will has some problem,the ServerMsgDecoder loop process the same one message

 forever, and then my server is abnormal.

05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
05-22 23:49:37.784 INFO ServerMsgDecoder - == 4^X�^@^@^@^M1463931910119
..........
..........
..........more and more same message

the '4^X�^@^@^@^M1463931910119' is in.toString which is the param of decode method in ServerMsgDecoder extends ByteToMessageDecoder

override def decode(
  ctx: ChannelHandlerContext,
  in: ByteBuf, out: util.List[AnyRef]
)

can someone help me? what happend? it caused by tcp packet splicing？