Question

如何保证netty执行事件是顺序而且高效

Answer 1

netty实现多个handler顺序调用在netty中，一次数据交互，可以由多个handler去处理，例如handler1和handler2，那么，在前面那个handler的messageReceived的最后要加上ctx.sendUpstream(e);理论请见：AChannelEventcanbehandledbyeitheraChannelUpstreamHandleroraChannelDownstreamHandlerandbeforwardedtotheclosesthandlerbycallingChannelHandlerContext.sendUpstream(ChannelEvent)orChannelHandlerContext.sendDownstream(ChannelEvent).代码：复制代码publicclassHandler1extendsSimpleChannelUpstreamHandler{@OverridepublicvoidmessageReceived(ChannelHandlerContextctx,MessageEvente){System.out.println("1messagereceived");Stringa="11";Objecto=a;ctx.getChannel().write(a);ctx.sendUpstream(e);}@OverridepublicvoidexceptionCaught(ChannelHandlerContextctx,ExceptionEvente)throwsException{e.getChannel().close();}}复制代码复制代码publicclassHandler2extendsSimpleChannelUpstreamHandler{@OverridepublicvoidmessageReceived(ChannelHandlerContextctx,MessageEvente){System.out.println("2messagereceived");e.getChannel().close();}@OverridepublicvoidexceptionCaught(ChannelHandlerContextctx,ExceptionEvente)throwsException{e.getChannel().close();}}复制代码复制代码publicclassTcpServer{publicstaticvoidmain(String[]args){System.out.println("startingatcpserver");ServerBootstrapsb=newServerBootstrap(newNioServerSocketChannelFactory(Executors.newCachedThreadPool(),Executors.newCachedThreadPool()));sb.setPipelineFactory(newPKServerPipelineFactory());sb.setOption("child.tcpNoDelay",true);sb.setOption("child.keepAlive",true);sb.bind(newInetSocketAddress(9999));}}

Answer 2

netty本身实现的长连接，就是一个连接一个worker。worker的数量是有限的（通常是cpu cores+1），所以你的服务器要是连接数多的话，得考虑使用“异步”Request（netty的http没实现这么个功能），或者说“Continuation”，当连接“无事可做”的时候