1 public class NettyOioServer {
 2     public  void server(int port) throws Exception{
 3         final ByteBuf buf = Unpooled.unreleasableBuffer(
 4                 Unpooled.copiedBuffer("hi\r\n", Charset.forName("UTF-8"))
 5         );
 6         //创建EventLoopGroup
 7         EventLoopGroup eventLoopGroup = new OioEventLoopGroup();
 8         try {
 9             //创建ServerBootstrap
10             ServerBootstrap serverBootstrap = new ServerBootstrap();
11             serverBootstrap.group(eventLoopGroup)
12                     //指定nio传输channel
13                     .channel(OioServerSocketChannel.class)
14                     //指定端口
15                     .localAddress(new InetSocketAddress(port))
16                     //添加一个echoServerHandler到子channel的channelPipeLine
17                     .childHandler(new ChannelInitializer<SocketChannel>() {
18                         protected void initChannel(SocketChannel socketChannel) throws Exception {
19                           socketChannel.pipeline().addLast(new ChannelInboundHandlerAdapter(){
20                               @Override
21                               public void channelActive(ChannelHandlerContext ctx) throws Exception {
22                                   ctx.writeAndFlush(buf.duplicate()).addListener(ChannelFutureListener.CLOSE);
23                               }
24                           });
25                         }
26                     });
27             //异步的绑定服务器，调用sync阻塞到绑定完成
28             ChannelFuture channelFuture = serverBootstrap.bind().sync();
29             //获取channel的closeFuture,并阻塞到其完成
30             channelFuture.channel().closeFuture().sync();
31         }finally {
32             //释放资源
33             eventLoopGroup.shutdownGracefully().sync();
34         }
35     }
36 }

1 EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
2 serverBootstrap.group(eventLoopGroup)
3                     //指定nio传输channel
4                     .channel(NioServerSocketChannel.class).。。。。

 1 public interface Channel extends AttributeMap, ChannelOutboundInvoker, Comparable<Channel> {
 2 
 3     EventLoop eventLoop();              //返回分配给channel的eventloop
 4 
 5     void write();                       //将数据写到远程节点，这个数据将被传递给channelpipeline，并排队直到它被冲刷
 6 
 7     boolean isActive();
 8 
 9     SocketAddress localAddress();
10 
11     SocketAddress remoteAddress();
12 
13     ChannelPipeline pipeline();         //返回分配给channel的pipeline
14 
15     Channel flush();                    //将之前写的数据冲刷到底层进行传输，如一个socket
16 
17     ...
18 }

 1 interface ChannelHandler{
 2       void channelReadable(Channel channel);
 3       void channelWritable(Channel channel);
 4    }
 5    class Channel{
 6      Socket socket;
 7      Event event;//读，写或者连接
 8    }
 9 
10    //IO线程主循环:
11    class IoThread extends Thread{
12    public void run(){
13    Channel channel;
14    while(channel=Selector.select()){//选择就绪的事件和对应的连接，如果没有I/O事件产生，我们的程序就会阻塞在select处，而不是空转！！！！
15       if(channel.event==OP_ACCEPT){
16          registerNewChannelHandler(channel);//如果是新连接，则注册一个新的读写处理器
17       }
18       if(channel.event==OP_WRITE){
19          getChannelHandler(channel).channelWritable(channel);//如果可以写，则执行写事件
20       }
21       if(channel.event==OP_READ){
22           getChannelHandler(channel).channelReadable(channel);//如果可以读，则执行读事件
23       }
24     }
25    }
26    Map<Channel，ChannelHandler> handlerMap;//所有channel的对应事件处理器
27   }

 1 ........
 2 //创建EventLoopGroup
 3         EventLoopGroup eventLoopGroup = new EpollEventLoopGroup();
 4         try {
 5             //创建ServerBootstrap
 6             ServerBootstrap serverBootstrap = new ServerBootstrap();
 7             serverBootstrap.group(eventLoopGroup)
 8                     //指定nio传输channel
 9                     .channel(EpollServerSocketChannel.class)
10                      ......