DUBBO Caused by: java.nio.channels.ClosedChannelException

[WARN ] 2016-02-19 09:39:57,735 --> [dubbo-remoting-client-heartbeat-thread-2] com.alibaba.dubbo.remoting.exchange.support.header.HeartBeatTask.run(HeartBeatTask.java:84):  [DUBBO] Exception when heartbeat to remote channel /192.168.17.27:20885, dubbo version: 2.4.9, current host: 192.168.17.27  
com.alibaba.dubbo.remoting.RemotingException: Failed to send message Request [id=4888, version=2.0.0, twoway=true, event=true, broken=false, data=null] to /192.168.17.27:50558, cause: null
    at com.alibaba.dubbo.remoting.transport.netty.NettyChannel.send(NettyChannel.java:108)
    at com.alibaba.dubbo.rpc.protocol.dubbo.ChannelWrappedInvoker$ChannelWrapper.send(ChannelWrappedInvoker.java:153)
    at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeChannel.send(HeaderExchangeChannel.java:87)
    at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeChannel.send(HeaderExchangeChannel.java:77)
    at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeClient.send(HeaderExchangeClient.java:111)
    at com.alibaba.dubbo.remoting.exchange.support.header.HeartBeatTask.run(HeartBeatTask.java:64)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:351)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:178)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:178)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
Caused by: java.nio.channels.ClosedChannelException
    at org.jboss.netty.channel.socket.nio.NioWorker.cleanUpWriteBuffer(NioWorker.java:643)
    at org.jboss.netty.channel.socket.nio.NioWorker.writeFromUserCode(NioWorker.java:370)
    at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.handleAcceptedSocket(NioServerSocketPipelineSink.java:137)
    at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.eventSunk(NioServerSocketPipelineSink.java:76)
    at org.jboss.netty.channel.Channels.write(Channels.java:632)
    at org.jboss.netty.handler.codec.oneone.OneToOneEncoder.handleDownstream(OneToOneEncoder.java:70)
    at com.alibaba.dubbo.remoting.transport.netty.NettyHandler.writeRequested(NettyHandler.java:99)
    at org.jboss.netty.channel.Channels.write(Channels.java:611)
    at org.jboss.netty.channel.Channels.write(Channels.java:578)
    at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:251)
    at com.alibaba.dubbo.remoting.transport.netty.NettyChannel.send(NettyChannel.java:98)
    ... 13 more

dubbo版本： 2.4.9
zookeeper版本 3.4.5
zookeeper.jar版本 3.4.6
zkclient-0.6.jar版本 0.6

重启下服务就完事了。

不是啥原因。