io.netty.util.IllegalReferenceCountException: refCnt: 0

• 1.将ByteBuf转为String存起来
• 2.取出消息时可以再转换为ByteBuf

//将buf传到其他类中使用时，ByteBuf可能被释放了
protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
	ByteBuf buf = packet.content();
}

//将buf转为String
@Override
protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
	ByteBuf buf = packet.content();
	String con = ByteBufUtil.hexDump(buf);
	log.info("收到udp数据：{}",con);
	//消息队列添加消息
	UdpQueueServer.queue.put(con);
}

public class UdpQueueServer{
	//消息队列
	public static BlockingQueue queue = new ArrayBlockingQueue<>(1024);
@Scheduled(fixedDelay = 3000)	
    public void consumerMessage() throws Exception {
        boolean isRunning = true;
        while (isRunning) {
            try {
				String con = (String) queue.take();		//取出队列中的数据
				if (con != null){
					log.info("内容：{}",con);
					//在转为ByteBuf
					byte[] bytes = ParseUtil.hexStringToBytes(con);
					ByteBuf buf = Unpooled.wrappedBuffer(bytes);
				} else {
					log.info("取出内容为null");
				}
				if(queue.remainingCapacity == 1024){
					isRunning = false;
				}
            } catch (Exception e) {
                e.printStackTrace();
                log.info("{}",e);
            }
        }
    }

	//String转16进制 byte[]
	public static byte[] hexStringToBytes(String hexString) {
		if (StringUtils.isEmpty(hexString)) {
			return null;
		}
		hexString = hexString.toUpperCase();
		int length = hexString.length() / 2;
		char[] hexChars = hexString.toCharArray();
		byte[] d = new byte[length];
		for (int i = 0; i < length; i++) {
			int pos = i * 2;
			d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
		}
		return d;
	}
}