一、加依赖

        <dependency><groupId>io.netty</groupId><artifactId>netty-all</artifactId><version>4.1.72.Final</version></dependency>

二、创建自定义的handler

package cn.edu.tju.handler;import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOutboundHandler;
import io.netty.channel.ChannelOutboundHandlerAdapter;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;import java.nio.ByteBuffer;public class MyHttpHandler extends SimpleChannelInboundHandler<HttpObject> {@Overrideprotected void channelRead0(ChannelHandlerContext ctx, HttpObject httpObject) throws Exception {System.out.println("get info from client...");String message = "hello, world";ByteBuf byteBuf = Unpooled.copiedBuffer(message.getBytes());FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,HttpResponseStatus.OK, byteBuf);response.headers().set(HttpHeaderNames.CONTENT_TYPE,"text/plain");response.headers().set(HttpHeaderNames.CONTENT_LENGTH, message.length() );ctx.channel().writeAndFlush(response);}
}

三、定义启动类，在pipeline中添加自定义的handler

package cn.edu.tju;import cn.edu.tju.handler.MyHttpHandler;
import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpServerCodec;public class NettyHttpServer {private static int port = 9093;public static void main(String[] args) {EventLoopGroup bossGroup=new NioEventLoopGroup();EventLoopGroup workerGroup=new NioEventLoopGroup();try{ServerBootstrap serverBootstrap=new ServerBootstrap();serverBootstrap.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class).childHandler(new ChannelInitializer<Channel>() {@Overrideprotected void initChannel(Channel channel) throws Exception {channel.pipeline().addLast("httpServerCodec", new HttpServerCodec());channel.pipeline().addLast("myHttpHandler", new MyHttpHandler());}});ChannelFuture channelFuture=serverBootstrap.bind(port).sync();channelFuture.channel().closeFuture().sync();}catch (Exception ex){}}
}