一、简介

netty是jboss提供的一个java开源框架,netty提供异步的、事件驱动的网络应用程序框架和工具,用以快速开发高性能、高可用性的网络服务器和客户端程序。也就是说netty是一个基于nio的编程框架,使用netty可以快速的开发出一个网络应用。

netty的核心是支持零拷贝的bytebuf缓冲对象、通用通信api和可扩展的事件模型;它支持多种传输服务并且支持HTTP、Protobuf、二进制、文本、WebSocket 等一系列常见协议,也支持自定义协议。

netty的模型是基于reactor多线程模型,其中mainReactor用于接收客户端请求并转发给subReactor。SubReactor负责通道的读写请求,非 IO 请求(具体逻辑处理)的任务则会直接写入队列,等待 worker threads 进行处理。

springboot netty怎么配置参数 springboot netty tcp_服务端

二、核心概念

  1. bootstrap、serverBootstrap:bootstrap的意思是引导,其主要作用是配置整个netty程序,将各个组件整合起来。serverBootstrap是服务器端的引导类。bootstrap用于连接远程主机它有一个EventLoopGroup ;serverBootstrap用于监听本地端口有两个EventLoopGroup。
  2. eventLoop:eventLoop维护了一个线程和任务队列,支持异步提交执行任务。
  3. eventLoopGroup:eventLoopGroup 主要是管理eventLoop的生命周期,可以将其看作是一个线程池,其内部维护了一组eventLoop,每个eventLoop对应处理多个Channel,而一个Channel只能对应一个eventLoop。
  4. channelPipeLine:是一个包含channelHandler的list,用来设置channelHandler的执行顺序。
  5. Channel:Channel代表一个实体(如一个硬件设备、一个文件、一个网络套接字或者一个能够执行一个或者多个不同的IO操作的程序组件)的开放链接,如读操作和写操作。
  6. Futrue、ChannelFuture :Future提供了另一种在操作完成时通知应用程序的方式。这个对象可以看作是一个异步操作结果的占位符;它将在未来的某个时刻完成,并提供对其结果的访问。netty的每一个出站操作都会返回一个ChannelFuture。future上面可以注册一个监听器,当对应的事件发生后会出发该监听器。
  7. ChannelInitializer:它是一个特殊的ChannelInboundHandler,当channel注册到eventLoop上面时,对channel进行初始化
  8. ChannelHandler:用来处理业务逻辑的代码,ChannelHandler是一个父接口,ChannelnboundHandler和ChannelOutboundHandler都继承了该接口,它们分别用来处理入站和出站。
  9. ChannelHandlerContext:允许与其关联的ChannelHandler与它相关联的ChannlePipeline和其它ChannelHandler来进行交互。它可以通知相同ChannelPipeline中的下一个ChannelHandler,也可以对其所属的ChannelPipeline进行动态修改。 

三、实现

服务端

依赖项

<dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.17.Final</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
        </dependency>

 启动项

import com.example.netty.netty.NettyServer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.net.InetAddress;
import java.net.InetSocketAddress;

@SpringBootApplication
public class NettyApplication implements CommandLineRunner {

    @Autowired
    private NettyServer nettyServer;

    private static final Logger log = LoggerFactory.getLogger(NettyApplication.class);

    @Override
    public void run(String... strings) throws Exception{
        //获取自己本机地址
        InetAddress inetAddress = InetAddress.getLocalHost();
        InetSocketAddress address = new InetSocketAddress(inetAddress.getHostAddress(),8085);
        log.info("netty服务的启动地址为:"+inetAddress.getHostAddress()+":"+"8085" );
        nettyServer.start(address);
    }

    public static void main(String[] args) {
        SpringApplication.run(NettyApplication.class, args);
    }

}

 配置文件

server.port=8089

netty服务启动类

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import java.net.InetSocketAddress;

/**
 * @description: netty服务启动类
 **/
 
@Slf4j
@Component
public class NettyServer {

    public void start(InetSocketAddress address) {
        //配置服务端的NIO线程组
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        
        try {
            ServerBootstrap bootstrap = new ServerBootstrap()
                    .group(bossGroup, workerGroup)  // 绑定线程池
                    .channel(NioServerSocketChannel.class)
                    .localAddress(address)
                    .childHandler(new NettyServerChannelInitializer())//编码解码
                    .option(ChannelOption.SO_BACKLOG, 128)  //服务端接受连接的队列长度,如果队列已满,客户端连接将被拒绝
                    .childOption(ChannelOption.SO_KEEPALIVE, true);  //保持长连接,2小时无数据激活心跳机制

            // 绑定端口,开始接收进来的连接
            ChannelFuture future = bootstrap.bind(address).sync();
            log.info("netty服务器开始监听端口:" + address.getPort());
            //关闭channel和块,直到它被关闭
            future.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

}

 服务端初始化

import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;

/**
 * @description: 服务端初始化,客户端与服务器端连接一旦创建,这个类中方法就会被回调,设置出站编码器和入站解码器
 **/

public class NettyServerChannelInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel channel) throws Exception {

        channel.pipeline().addLast("decoder",new StringDecoder(CharsetUtil.UTF_8));
        channel.pipeline().addLast("encoder",new StringEncoder(CharsetUtil.UTF_8));
        channel.pipeline().addLast(new NettyServerHandler());
    }
}

 netty服务端处理类

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelId;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import lombok.extern.slf4j.Slf4j;

import java.net.InetSocketAddress;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @description: netty服务端处理类
 **/

@Slf4j
public class NettyServerHandler extends ChannelInboundHandlerAdapter {

    /**
     * 管理一个全局map,保存连接进服务端的通道数量
     */
    private static final ConcurrentHashMap<ChannelId, ChannelHandlerContext> CHANNEL_MAP = new ConcurrentHashMap<>();

    /**
     * @param ctx
     * @author xiongchuan on 2019/4/28 16:10
     * @DESCRIPTION: 有客户端连接服务器会触发此函数
     * @return: void
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) {

        InetSocketAddress insocket = (InetSocketAddress) ctx.channel().remoteAddress();

        String clientIp = insocket.getAddress().getHostAddress();
        int clientPort = insocket.getPort();

        //获取连接通道唯一标识
        ChannelId channelId = ctx.channel().id();

        System.out.println();
        //如果map中不包含此连接,就保存连接
        if (CHANNEL_MAP.containsKey(channelId)) {
            log.info("客户端【" + channelId + "】是连接状态,连接通道数量: " + CHANNEL_MAP.size());
        } else {
            //保存连接
            CHANNEL_MAP.put(channelId, ctx);

            log.info("客户端【" + channelId + "】连接netty服务器[IP:" + clientIp + "--->PORT:" + clientPort + "]");
            log.info("连接通道数量: " + CHANNEL_MAP.size());
        }
    }

    /**
     * @param ctx
     * @author xiongchuan on 2019/4/28 16:10
     * @DESCRIPTION: 有客户端终止连接服务器会触发此函数
     * @return: void
     */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) {

        InetSocketAddress insocket = (InetSocketAddress) ctx.channel().remoteAddress();

        String clientIp = insocket.getAddress().getHostAddress();

        ChannelId channelId = ctx.channel().id();

        //包含此客户端才去删除
        if (CHANNEL_MAP.containsKey(channelId)) {
            //删除连接
            CHANNEL_MAP.remove(channelId);

            System.out.println();
            log.info("客户端【" + channelId + "】退出netty服务器[IP:" + clientIp + "--->PORT:" + insocket.getPort() + "]");
            log.info("连接通道数量: " + CHANNEL_MAP.size());
        }
    }

    /**
     * @param ctx
     * @author xiongchuan on 2019/4/28 16:10
     * @DESCRIPTION: 有客户端发消息会触发此函数
     * @return: void
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

        log.info("加载客户端报文......");
        log.info("【" + ctx.channel().id() + "】" + " :" + msg);

        /**
         *  下面可以解析数据,保存数据,生成返回报文,将需要返回报文写入write函数
         *
         */

        //响应客户端
//        this.channelWrite(ctx.channel().id(), msg);

        //广播给所有人
        this.channelWriteAll(msg);
    }

    /**
     * @param msg        需要发送的消息内容
     * @param channelId 连接通道唯一id
     * @author xiongchuan on 2019/4/28 16:10
     * @DESCRIPTION: 服务端给客户端发送消息
     * @return: void
     */
    public void channelWrite(ChannelId channelId, Object msg) throws Exception {

        ChannelHandlerContext ctx = CHANNEL_MAP.get(channelId);

        if (ctx == null) {
            log.info("通道【" + channelId + "】不存在");
            return;
        }

        if (msg == null || msg == "") {
            log.info("服务端响应空的消息");
            return;
        }

        //将客户端的信息直接返回写入ctx
        ctx.write(msg);
        //刷新缓存区
        ctx.flush();
    }



    //广播给所有人
    public void channelWriteAll( Object msg) throws Exception {

        if (CHANNEL_MAP.size() == 00) {
            log.info("通道不存在");
            return;
        }

        if (msg == null || msg == "") {
            log.info("服务端响应空的消息");
            return;
        }

        for (ChannelHandlerContext ctx: CHANNEL_MAP.values()){
            //将客户端的信息直接返回写入ctx
            ctx.write(msg);
            //刷新缓存区
            ctx.flush();
        }

    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {

        String socketString = ctx.channel().remoteAddress().toString();

        if (evt instanceof IdleStateEvent) {
            IdleStateEvent event = (IdleStateEvent) evt;
            if (event.state() == IdleState.READER_IDLE) {
                log.info("Client: " + socketString + " READER_IDLE 读超时");
                ctx.disconnect();
            } else if (event.state() == IdleState.WRITER_IDLE) {
                log.info("Client: " + socketString + " WRITER_IDLE 写超时");
                ctx.disconnect();
            } else if (event.state() == IdleState.ALL_IDLE) {
                log.info("Client: " + socketString + " ALL_IDLE 总超时");
                ctx.disconnect();
            }
        }
    }

    /**
     * @param ctx
     * @author xiongchuan on 2019/4/28 16:10
     * @DESCRIPTION: 发生异常会触发此函数
     * @return: void
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {

        System.out.println();
        ctx.close();
        log.info(ctx.channel().id() + " 发生了错误,此连接被关闭" + "此时连通数量: " + CHANNEL_MAP.size());
        //cause.printStackTrace();
    }
}

 整个项目的目录如下:

springboot netty怎么配置参数 springboot netty tcp_服务端_02

客户端 

客户端

package com.example.demo.client;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;

import java.util.Date;
import java.util.Scanner;

/**
 * @description: 客户端
 **/

@Slf4j
@Data
public class NettyClient implements Runnable {
    //你netty服务的ip,自己更换,本机就是127.0.0.1
    static final String HOST = System.getProperty("host", "10.0.5.60");
    static final int PORT = Integer.parseInt(System.getProperty("port", "8085"));
    static final int SIZE = Integer.parseInt(System.getProperty("size", "256"));

    private String content;

    public NettyClient(String content) {
        this.content = content;
    }

    @Override
    public void run() {
        // Configure the client.
        EventLoopGroup group = new NioEventLoopGroup();
        try {

            int num = 0;
            boolean boo = true;

            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.TCP_NODELAY, true)
                    .handler(new NettyClientChannelInitializer() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline p = ch.pipeline();
                            p.addLast("decoder", new StringDecoder());
                            p.addLast("encoder", new StringEncoder());
                            p.addLast(new NettyClientHandler());
                        }
                    });

            ChannelFuture future = b.connect(HOST, PORT).sync();

            while (boo) {

                num++;

                future.channel().writeAndFlush(content);

                try { //休眠一段时间
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                //每一条线程向服务端发送的次数
                if (num == 100) {
                    boo = false;
                }
            }

            System.out.println(content + "-----------------------------" + num);
            future.channel().closeFuture().sync();
//            Scanner input = new Scanner(System.in);
//            int i = input.nextInt();
//            System.out.println(i);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            group.shutdownGracefully();
        }
    }

    /**
     *  下面是不加线程的
     */
    /*public static void main(String[] args) throws Exception {

        sendMessage("hhh你好?");
    }

    public static void sendMessage(String content) throws InterruptedException {
        // Configure the client.
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.TCP_NODELAY, true)
                    .handler(new NettyClientChannelInitializer() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline p = ch.pipeline();
                            p.addLast("decoder", new StringDecoder());
                            p.addLast("encoder", new StringEncoder());
                            p.addLast(new NettyClientHandler());
                        }
                    });

            ChannelFuture future = b.connect(HOST, PORT).sync();
            future.channel().writeAndFlush(content);
            future.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }*/

}

 客户端初始化 

import com.example.demo.netty.NettyServerHandler;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;

/**
 * @description: 客户端初始化,客户端与服务器端连接一旦创建,这个类中方法就会被回调,设置出站编码器和入站解码器,客户端服务端编解码要一致
 **/

public class NettyClientChannelInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel channel) throws Exception {

        channel.pipeline().addLast("decoder",new StringDecoder(CharsetUtil.UTF_8));
        channel.pipeline().addLast("encoder",new StringEncoder(CharsetUtil.UTF_8));

        channel.pipeline().addLast(new NettyServerHandler());
    }
}
客户端处理类
/**
 * @description: 客户端处理类
 **/

@Slf4j
public class NettyClientHandler extends ChannelInboundHandlerAdapter {

    /**
     * 计算有多少客户端接入,第一个string为客户端ip
     */
    private static final ConcurrentHashMap<ChannelId, ChannelHandlerContext> CLIENT_MAP = new ConcurrentHashMap<>();

    @Override
    public void channelActive(ChannelHandlerContext ctx) {

        CLIENT_MAP.put(ctx.channel().id(), ctx);

        System.out.println("ClientHandler Active");
    }

    /**
     * @param ctx
     * @author xiongchuan on 2019/4/28 16:10
     * @DESCRIPTION: 有服务端端终止连接服务器会触发此函数
     * @return: void
     */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) {

        ctx.close();
        System.out.println("服务端终止了服务");
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        System.out.println("回写数据:" + msg);
    }


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

        //cause.printStackTrace();
        System.out.println("服务端发生异常【" + cause.getMessage() + "】");
        ctx.close();
    }

    /**
     * @param msg       需要发送的消息内容
     * @param channelId 连接通道唯一id
     * @author xiongchuan on 2019/4/28 16:10
     * @DESCRIPTION: 客户端给服务端发送消息
     * @return: void
     */
    public void channelWrite(ChannelId channelId, String msg) {

        ChannelHandlerContext ctx = CLIENT_MAP.get(channelId);

        if (ctx == null) {
            System.out.println("通道【" + channelId + "】不存在");
            return;
        }

        //将客户端的信息直接返回写入ctx
        ctx.write(msg );
        //刷新缓存区
        ctx.flush();
    }
}

 程序启动

public static void main(String[] args) {
        new Thread(new NettyClient("thread" + "--1" )).start();
    }

四、测试

先启动服务端,然后启动客户端main方法,

服务端会看到:

springboot netty怎么配置参数 springboot netty tcp_服务端_03

客户端会看到: 

springboot netty怎么配置参数 springboot netty tcp_服务端_04