netty03-netty基础

我会带着你远行 2022-05-31 04:41 153阅读 0赞

#  #

# **what** #

![SouthEast][]

# **netty架构** #

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*  Extensible Event Model-可扩展的事件模型
 *  Universal Communication API-统一的通讯API
 *  Zero-Copy-Capable Rich Byte Buffer-零拷贝的Buffer
 *  Transport Services-传输层服务
 *  Protocol Support-应用层协议支持

## **Netty模块/组件** ##

*  bootstrap  Netty服务端及客户端启动类
 *  buffer  缓冲相关，对NIO Buffer做了一些优化、封装
 *  channel 处理客户端与服务端之间的连接通道
 *  container 连接其他容器的代码，例如Spring
 *  handler 实现协议编解码等附加功能，
 *  logging 日志
 *  util工具类

## **Netty主从多线程Reactor模式** ##

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对应关系：

MainReactor = NioServerBoss

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SubReactor = NioWorker

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# **Neety服务端基本实现** #

package com.hotpot.netty03;
    
     
    
    import java.net.InetSocketAddress;
    
    import java.util.concurrent.ExecutorService;
    
    import java.util.concurrent.Executors;
    
     
    
    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.codec.string.StringDecoder;
    
    import org.jboss.netty.handler.codec.string.StringEncoder;
    
     
    
    /**
    
     * 描述:netty服务端
    
     * @author: myx
    
     * @date: 2018/2/7 0007
    
     * Copyright © 2018-ganinfo. All rights reserved.
    
     */
    
    public class Server {
    
       public static void main(String[] args) {
    
          // 服务类
    
          ServerBootstrap bootstrap = new ServerBootstrap();
    
          
    
          // boss线程，主要监听端口和获取worker线程及分配socketChannel给worker线程
    
          ExecutorService boss = Executors.newCachedThreadPool();
    
          // worker线程负责数据读写
    
          ExecutorService worker = Executors.newCachedThreadPool();
    
          
    
          // 设置niosocket工厂
    
          bootstrap.setFactory(new NioServerSocketChannelFactory(boss, worker));
    
          
    
          // 设置管道的工厂
    
          bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
    
             
    
             @Override
    
             public ChannelPipeline getPipeline() throws Exception {
    
                ChannelPipeline pipeline = Channels.pipeline();
    
                // 管道过滤器
    
                pipeline.addLast("decoder", new StringDecoder());
    
                pipeline.addLast("encoder", new StringEncoder());
    
                pipeline.addLast("myServerMessageHandler", new MyServerMessageHandler());
    
                return pipeline;
    
             }
    
          });
    
          // 服务类绑定端口
    
          bootstrap.bind(new InetSocketAddress(7777));
    
          System.out.println("服务端启动...");
    
       }
    
    }

package com.hotpot.netty03;
    
     
    
    import org.jboss.netty.channel.ChannelHandlerContext;
    
    import org.jboss.netty.channel.ChannelStateEvent;
    
    import org.jboss.netty.channel.ExceptionEvent;
    
    import org.jboss.netty.channel.MessageEvent;
    
    import org.jboss.netty.channel.SimpleChannelHandler;
    
    /**
    
     * 描述:消息处理类
    
     * @author: myx
    
     * @date: 2018/2/7 0007
    
     * Copyright © 2018-ganinfo. All rights reserved.
    
     */
    
    public class MyServerMessageHandler extends SimpleChannelHandler {
    
       /**
    
        * 接收消息
    
        */
    
       @Override
    
       public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
    
          System.out.println("messageReceived");
    
          
    
          String s = (String) e.getMessage();
    
          System.out.println("服务端收到数据："+s);
    
          
    
          //回写数据给客户端
    
          ctx.getChannel().write("hello...");
    
          super.messageReceived(ctx, e);
    
       }
    
     
    
       /**
    
        * 异常处理
    
        */
    
       @Override
    
       public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
    
          System.out.println("exceptionCaught");
    
          super.exceptionCaught(ctx, e);
    
       }
    
     
    
       /**
    
        * 获取新连接事件
    
        */
    
       @Override
    
       public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
    
          System.out.println("channelConnected");
    
          super.channelConnected(ctx, e);
    
       }
    
     
    
       /**
    
        * 关闭通道的时候触发 （必须是链接已经建立）
    
        */
    
       @Override
    
       public void channelDisconnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
    
          System.out.println("channelDisconnected");
    
          super.channelDisconnected(ctx, e);
    
       }
    
     
    
       /**
    
        * 通道关闭的时候触发
    
        */
    
       @Override
    
       public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
    
          System.out.println("channelClosed");
    
          super.channelClosed(ctx, e);
    
       }
    
    }

## **boss、worker处理流程** ##

1. 标记nio selector唤醒状态（wakeUp状态位）

2. Selector（注册）

3. 处理任务队列

4. 处理自己的业务（客户端的读写请求等）

代码抽象：

![SouthEast 5][]

[SouthEast]: /images/20220531/fbeb65909f654ac2b088c560d38b65fc.png
[SouthEast 1]: /images/20220531/77c8adb3fa9043ee9447ef6f948aa735.png
[SouthEast 2]: /images/20220531/14b0ba01eea74876b439188c4a6099d0.png
[SouthEast 3]: /images/20220531/bb758768e8504d5b9250425f27dc7ebe.png
[SouthEast 4]: /images/20220531/602154d7b01d47519197c873188e40b5.png
[SouthEast 5]: /images/20220531/785abd9e201143b3a3ef18cf2cbbb2fc.png