netty技术实现即时通信方案

nettynetty是啥netty是jboss下的是开源项目。一个封装Socket的jar。可以快速开发高性能，高可靠的网络服务器与客户端程序。与apache下的mina是同一个作者（TrustinLee），并且是优化版。netty的优点1.开发简单，完整的Doc和用户样例，适用于不同的协议。2.基于灵活，可扩展的事件驱动模型。3.可靠soket支持，高度可定制的线程模型。4.更好的吞吐量，低延迟，节省资源，内部优化成熟，减少不必要的内存拷贝5.能与android环境运行良好。6.完整的SSL/TLS和STARTTLS的支持Netty整体架构

Netty组件

ChannelFactoryBossWorkerChannelChannelEventPipelineChannelContextHandlerSink

Server端核心类NioServerSocketChannelFactoryNioServerBossPool

NioWorkerPoolNioServerBossNioWorkerNioServerSocketChannelNioAcceptedSocketChannelDefaultChannelPipelineNioServerSocketPipelineSinkChannels

ChannelFactoryChannel工厂，很重要的类保存启动的相关参数

NioServerSocketChannelFactoryNioClientSocketChannelFactoryNioDatagramChannelFactory

这是Nio的，还有Oio和Local的

SelectorPool

Selector的线程池

NioServerBossPool默认线程数：1NioClientBossPool

1NioWorkerPool

2*ProcessorNioDatagramWorkerPool

Selector

选择器，很核心的组件

NioServerBossNioClientBossNioWorkerNioDatagramWorker

Channel

通道

NioServerSocketChannelNioClientSocketChannelNioAcceptedSocketChannelNioDatagramChannel

Sink负责和底层的交互如bind，Write，Close等

NioServerSocketPipelineSinkNioClientSocketPipelineSinkNioDatagramPipelineSink

Pipeline负责维护所有的Handler

ChannelContext一个Channel一个，是Handler和Pipeline的中间件

Handler对Channel事件的处理器

ChannelPipeline

优秀的设计----事件驱动

优秀的设计----线程模型

案例Server端：package;import;import.*;importty.channel.socket.nio.NioServerSocketChannelFactory;import;import;import;import;/***GodBlessYou!*Author:Fangniude*Date:2013-07-15*/publicclassNettyServer{publicstaticvoidmain(String[]args){ServerBootstrapbootstrap=newServerBootstrap(newNioServerSocketChannelFactory(Executors.newCachedThreadPool(),Executors.newCachedThreadPool()));//Setupthedefaulteventpipeline.bootstrap.setPipelineFactory(newChannelPipelineFactory(){@OverridepublicChannelPipelinegetPipeline()throwsException{returnChannels.pipeline(newStringDecoder(),newStringEncoder(),newServerHandler());}});//Bindandstarttoacceptincomingconnections.Channelbind=bootstrap.bind(newInetSocketAddress(8000));("Server已经启动，监听端口:"+bind.getLocalAddress()+"，等待客户端注册。。。");}privatestaticclassServerHandlerextendsSimpleChannelHandler{@OverridepublicvoidmessageReceived(ChannelHandlerContextctx,MessageEvente)throwsException{if(e.getMessage()instanceofString){Stringmessage=(String)e.getMessage();("Client发来:"+message);e.getChannel().write("Server已收到刚发送的:"+message);("\n等待客户端输入。。。");}super.messageReceived(ctx,e);}@OverridepublicvoidexceptionCaught(ChannelHandlerContextctx,ExceptionEvente)throwsException{super.exceptionCaught(ctx,e);}@OverridepublicvoidchannelConnected(ChannelHandlerContextctx,ChannelStateEvente)throwsException{("有一个客户端注册上来了。。。");("Client:"+e.getChannel().getRemoteAddress());("Server:"+e.getChannel().getLocalAddress());("\n等待客户端输入。。。");super.channelConnected(ctx,e);}}}客户端：package;import;import.*;importty.channel.socket.nio.NioClientSocketChannelFactory;import;import;import;import;import;import;/***GodBlessYou!*Author:Fangniude*Date:2013-07-15*/publicclassNettyClient{publicstaticvoidmain(String[]args){//Configuretheclient.ClientBootstrapbootstrap=newClientBootstrap(newNioClientSocketChannelFactory(Executors.newCachedThreadPool(),Executors.newCachedThreadPool()));//Setupthedefaulteventpipeline.bootstrap.setPipelineFactory(newChannelPipelineFactory(){@OverridepublicChannelPipelinegetPipeline()throwsException{returnChannels.pipeline(newStringDecoder(),newStringEncoder(),newClientHandler());}});//Starttheconnectionattempt.ChannelFuturefuture=bootstrap.connect(newInetSocketAddress("localhost",8000));//Waituntiltheconnectionisclosedortheconnectionattemptfails.future.getChannel().getCloseFuture().awaitUninterruptibly();//Shutdownthreadpoolstoexit.bootstrap.releaseExternalResources();}privatestaticclassClientHandlerextendsSimpleChannelHandler{privateBufferedReadersin=newBufferedReader(newInputStreamReader(System.in));@OverridepublicvoidmessageReceived(ChannelHandlerContextctx,MessageEvente)throwsException{if(e.getMessage()instanceofString){Stringmessage=(String)e.getMessage();(message);e.getChannel().write(sin.readLine());("\n等待客户端输入。。。");}super.messageReceived(ctx,e);}@Overridepu