netty demo

ReadMe

先运行 NettyServer

再运行 NettyClient

环境

netty 各种版本 pom

https://mvnrepository.com/artifact/io.netty/netty-all

jdk11；

pom

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.67.Final</version>
</dependency>

NettyServer.java

package com.lhh.demo.netty.simple;

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.ServerSocketChannel;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public class NettyServer {

    public static void main(String[] args) throws Exception{
        EventLoopGroup boos = new NioEventLoopGroup();
        EventLoopGroup worker = new NioEventLoopGroup();

        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(boos,worker)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG,128)
                    .childOption(ChannelOption.SO_KEEPALIVE,true)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            System.out.println("客户端上线了："+ch.remoteAddress());
                            ch.pipeline().addLast(new NettyServerHandler());
                        }
                    });

            System.out.println(" server is ready ....");
            ChannelFuture sync = bootstrap.bind(9999).sync();
            sync.channel().closeFuture().sync();
        } catch (Exception e){
            e.printStackTrace();
        } finally {
            worker.shutdownGracefully();
            boos.shutdownGracefully();
        }

    }
}

NettyServerHandler.java

package com.lhh.demo.netty.simple;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

import java.util.concurrent.TimeUnit;

public class NettyServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("ctx="+ctx);
        ByteBuf buf = (ByteBuf) msg;
        System.out.println("客户端对服务器说："+buf.toString(CharsetUtil.UTF_8));
        System.out.println("接收消息线程："+Thread.currentThread().getName());
        ctx.channel().eventLoop().execute(()->{
            try {
                System.out.println("task处理消息线程："+Thread.currentThread().getName());
                TimeUnit.SECONDS.sleep(10);
                ctx.writeAndFlush(Unpooled.copiedBuffer("hello 客户端；",CharsetUtil.UTF_8));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });
        System.out.println("sync execute business..........");
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {

        ctx.write(Unpooled.copiedBuffer("hello 客户端；",CharsetUtil.UTF_8));
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
            throws Exception {

        cause.printStackTrace();
        ctx.close();
    }

}

NettyClient.java

package com.lhh.demo.netty.simple;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;

public class NettyClient {

    public static void main(String[] args) throws Exception{

        NioEventLoopGroup group = new NioEventLoopGroup();

        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new NettyClientHandler());
                        }
                    });

            ChannelFuture future = bootstrap.connect("localhost", 9999).sync();
            future.channel().closeFuture().sync();

        } catch (Exception e){
            e.printStackTrace();
        }finally {
            group.shutdownGracefully();
        }

    }
}

NettyClientHandler.java

package com.lhh.demo.netty.simple;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

public class NettyClientHandler extends ChannelInboundHandlerAdapter {

    //客户端链接服务器完成，可以发送数据了
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        String str = "hello server";
        System.out.println("客户端对服务器说："+str);
        ctx.write(Unpooled.copiedBuffer(str, CharsetUtil.UTF_8));
        ctx.flush();
    }

    //接收到服务器段发送的数据，读取一下
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf buf = (ByteBuf) msg;
        System.out.println("服务器说："+buf.toString(CharsetUtil.UTF_8));
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
            throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}