1、我们在使用netty的是有都会存在将channelBuffer的数据处理成相应的String或者自定义数据。而这里主要是介绍管道里面存在的上行和下行的数据处理方式

　　2、通过一张图片来看一下具体管道中的实现过程

　　

　　一个Channel中包括一个Socket、一个ChannelPipeline。一个ChannelPipeline中有一个ChannelSink和多个ChannelHandler。ChannelHandler分为两种：UpstremHandler、DownstreamHandler。

　　不论是读数据还是写数据都要经过Channel中的ChannelPipeline。读数据的过程是从Socket到ChannelPipeline，由ChannelPipeline交给里面的UpstreamHandler（或者叫做InBoundHandler）从下到上依次处理 。写数据时，由要经过ChannelPipeline里面在DownStreamHandler（或者是OutBoundHandler）由上到下依次处理。

　　3、因为UpstremHandler与DownstreamHandler的实现方式大同小异，我这里写的例子是UpstremHandler的例子

package com.troy.application.upstream;import org.jboss.netty.bootstrap.ServerBootstrap;import org.jboss.netty.channel.ChannelPipeline;import org.jboss.netty.channel.ChannelPipelineFactory;import org.jboss.netty.channel.Channels;import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;import org.jboss.netty.handler.timeout.IdleStateHandler;import org.jboss.netty.util.HashedWheelTimer;import java.net.InetSocketAddress;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class Server {    public static void main(String[] args) {        //声明服务类        ServerBootstrap serverBootstrap = new ServerBootstrap();        //设定线程池        ExecutorService boss = Executors.newCachedThreadPool();        ExecutorService work = Executors.newCachedThreadPool();        //设置工厂        serverBootstrap.setFactory(new NioServerSocketChannelFactory(boss,work));        //设置管道流        serverBootstrap.setPipelineFactory(new ChannelPipelineFactory() {            @Override            public ChannelPipeline getPipeline() throws Exception {                ChannelPipeline channelPipeline = Channels.pipeline();                //添加处理方式                channelPipeline.addLast("idle",new IdleStateHandler(new HashedWheelTimer(),5,5,10));                channelPipeline.addLast("handler1",new Handler1());                channelPipeline.addLast("handler2",new Handler2());                return channelPipeline;            }        });        //设置端口        serverBootstrap.bind(new InetSocketAddress(9000));    }}

package com.troy.application.upstream;import org.jboss.netty.buffer.ChannelBuffer;import org.jboss.netty.channel.ChannelHandlerContext;import org.jboss.netty.channel.MessageEvent;import org.jboss.netty.channel.SimpleChannelHandler;import org.jboss.netty.channel.UpstreamMessageEvent;public class Handler1 extends SimpleChannelHandler {    @Override    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {        ChannelBuffer channelBuffer = (ChannelBuffer) e.getMessage();        byte[] array = channelBuffer.array();        String message = new String(array);        System.out.println("handler1"+message);        ctx.sendUpstream(new UpstreamMessageEvent(ctx.getChannel(),message,e.getRemoteAddress()));    }}

package com.troy.application.upstream;import org.jboss.netty.channel.ChannelHandlerContext;import org.jboss.netty.channel.MessageEvent;import org.jboss.netty.channel.SimpleChannelHandler;public class Handler2 extends SimpleChannelHandler {    @Override    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {        String message = (String) e.getMessage();        System.out.println("handler2"+message);    }}

　　说明：这里最重要的两个方法是sendUpstream和sendDownstream。这两个方式在上行和下行的处理基本上是一样的。在源码里面handler的处理都会存在sendUpstream和sendDownstream。这个两个方法也是多重处理的基础。