Netty4.0问题及解决——ChannelPipelineException
刚开始写了个简单的TCP服务端，测试也ok，但发现我用工具连上端口后，断开再连接就报了下面的错误。
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2013-03-26 13:54:05,283 WARN - Failed to initialize a channel. Closing: [id: 0x83d224f6, /127.0.0.1:2810 => /127.0.0.1:8080]io.netty.channel.ChannelPipelineException: com.cocoon.test.netty.codec.MessageCodec is not a @Sharable handler, so can't be added or removed multiple times.at io.netty.channel.DefaultChannelPipeline.callBeforeAdd(DefaultChannelPipeline.java:628)at io.netty.channel.DefaultChannelPipeline.addLast0(DefaultChannelPipeline.java:200)at io.netty.channel.DefaultChannelPipeline.addLast(DefaultChannelPipeline.java:173)at io.netty.channel.DefaultChannelPipeline.addLast(DefaultChannelPipeline.java:161)at com.cocoon.test.netty.handler.PipelineFactory.initChannel(PipelineFactory.java:27)at com.cocoon.test.netty.handler.PipelineFactory.initChannel(PipelineFactory.java:1)at io.netty.channel.ChannelInitializer.channelRegistered(ChannelInitializer.java:70)at io.netty.channel.DefaultChannelHandlerContext.invokeChannelRegistered(DefaultChannelHandlerContext.java:673)at io.netty.channel.DefaultChannelHandlerContext.fireChannelRegistered(DefaultChannelHandlerContext.java:659)at io.netty.channel.DefaultChannelPipeline.fireChannelRegistered(DefaultChannelPipeline.java:957)at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:608)at io.netty.channel.AbstractChannel$AbstractUnsafe.access$700(AbstractChannel.java:437)at io.netty.channel.AbstractChannel$AbstractUnsafe$5.run(AbstractChannel.java:585)at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:328)at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:331)at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:109)at java.lang.Thread.run(Thread.java:619)
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后来发现需要在报错的handler前面加上@sharable，比如：
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@Sharablepublic class TcpServerHandler extends ChannelInboundMessageHandlerAdapter<String> {private static final Logger logger = Logger.getLogger(TcpServerHandler.class.getName());@Overridepublic void messageReceived(ChannelHandlerContext ctx, String request) throws Exception {logger.info("Receive:" + request);ChannelFuture future = ctx.write(request);future.addListener(ChannelFutureListener.CLOSE);}@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {logger.log(Level.WARNING, "Unexpected exception from downstream.", cause);ctx.close();}}?
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这样就行了。