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添加Maven依赖

        <dependency>            <groupId>io.netty</groupId>            <artifactId>netty-all</artifactId>            <version>4.1.36.Final</version>        </dependency>

代码示例：

import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.*;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioServerSocketChannel;import io.netty.handler.codec.string.StringDecoder;import io.netty.handler.codec.string.StringEncoder;public class NetttyServer{    public static void main(String[] args)    {        EventLoopGroup boss = new NioEventLoopGroup();        EventLoopGroup worker = new NioEventLoopGroup();        ServerBootstrap bootstrap = new ServerBootstrap();        bootstrap.group(boss,worker)                .channel(NioServerSocketChannel.class)                .childHandler(new ChannelInitializer<SocketChannel>()                {                    @Override                    protected void initChannel(SocketChannel socketChannel) throws Exception                    {                        socketChannel.pipeline()                                .addLast("encoder",new StringEncoder())                                .addLast("decoder",new StringDecoder())                                .addLast("hello world hanlder",new HelloWorldHandler());                    }                });        try        {            ChannelFuture channelFuture = bootstrap.bind(8080).sync();            channelFuture.channel().closeFuture().sync();        } catch (InterruptedException e){            e.printStackTrace();        }finally        {            boss.shutdownGracefully();            worker.shutdownGracefully();        }    }    static class HelloWorldHandler extends ChannelInboundHandlerAdapter    {        @Override        public void channelActive(ChannelHandlerContext ctx) throws Exception        {            System.out.println("channel Active and write back......");            String resp = "Hello world";            ChannelFuture future = ctx.channel().writeAndFlush(resp);            future.sync();            System.out.println("success:"+future.isSuccess());            //super.channelActive(ctx);        }        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {            System.out.println("read msg : "+msg);            String resp = "Hello world";            ctx.channel().writeAndFlush(resp);        }    }}