Netty学习笔记

package io.netty.example.discard;import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelInitializer;import io.netty.channel.ChannelOption;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioServerSocketChannel;/** 1. Discards any incoming data. */public class DiscardServer {    private int port;    public DiscardServer(int port) {        this.port = port;    }    public void run() throws Exception {        EventLoopGroup bossGroup = new NioEventLoopGroup(); // (1)        EventLoopGroup workerGroup = new NioEventLoopGroup();        try {            ServerBootstrap b = new ServerBootstrap(); // (2)            b.group(bossGroup, workerGroup)             .channel(NioServerSocketChannel.class) // (3)             .childHandler(new ChannelInitializer<SocketChannel>() { // (4)                 @Override                 public void initChannel(SocketChannel ch) throws Exception {                     ch.pipeline().addLast(new DiscardServerHandler());                 }             })             .option(ChannelOption.SO_BACKLOG, 128)          // (5)             .childOption(ChannelOption.SO_KEEPALIVE, true); // (6)            // Bind and start to accept incoming connections.            ChannelFuture f = b.bind(port).sync(); // (7)            // Wait until the server socket is closed.            // In this example, this does not happen, but you can do that to gracefully            // shut down your server.            f.channel().closeFuture().sync();        } finally {            workerGroup.shutdownGracefully();            bossGroup.shutdownGracefully();        }    }    public static void main(String[] args) throws Exception {        int port;        if (args.length > 0) {            port = Integer.parseInt(args[0]);        } else {            port = 8080;        }        new DiscardServer(port).run();    }}

NioEventLoopGroup 多线程，不同的实现，对于这两个线程Group而言怎么创建channel，怎么实现多线程，根据其内部实现不同而不同，并且可以配置。
1. boss：接收到来的请求
2. worker:处理接收到的请求

ServerBottstrap用来建立server的帮助类

NioServerSocketChannel 用来实例化新的channel来接收到来的请求

ChannelInitializer帮助用户配置新的channel，可以使用 ChannelPipeline来添加新的channel

ChannelOption
ChannelConfig