创建一个SpringBoot工程,然后创建三个子模块
整体工程目录:一个server服务(netty服务器),两个client服务(netty客户端)

pom文件引入netty依赖,springboot依赖
4.0.0 pom server client1 client2 org.springframework.boot spring-boot-starter-parent 2.2.1.RELEASE org.example nettyTest 1.0-SNAPSHOT org.apache.maven.plugins maven-compiler-plugin 8 8 org.springframework.boot spring-boot-starter-web io.netty netty-all 4.1.34.Final org.projectlombok lombok 1.16.18 org.slf4j slf4j-api com.alibaba fastjson 1.1.23

NettySpringBootApplication
package server;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class NettySpringBootApplication {
public static void main(String[] args) {
SpringApplication.run(NettySpringBootApplication.class, args);
}
}
NettyServiceHandler
package server.netty; import io.netty.channel.Channel; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.channel.group.ChannelGroup; import io.netty.channel.group.DefaultChannelGroup; import io.netty.util.concurrent.GlobalEventExecutor; public class NettyServiceHandler extends SimpleChannelInboundHandler{ private static final ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { // 获取到当前与服务器连接成功的channel Channel channel = ctx.channel(); group.add(channel); System.out.println(channel.remoteAddress() + " 上线," + "在线数量:" + group.size()); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { // 获取到当前要断开连接的Channel Channel channel = ctx.channel(); System.out.println(channel.remoteAddress() + "下线," + "在线数量:" + group.size()); } @Override protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception { Channel channel = ctx.channel(); System.out.println("netty客户端" + channel.remoteAddress() + "发送过来的消息:" + msg); group.forEach(ch -> { // JDK8 提供的lambda表达式 if (ch != channel) { ch.writeAndFlush(channel.remoteAddress() + ":" + msg + "\n"); } }); } public void exceptionCaught(ChannelHandlerContext channelHandlerContext, Throwable throwable) throws Exception { throwable.printStackTrace(); channelHandlerContext.close(); } }
SocketInitializer
package server.netty; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.LineBasedFrameDecoder; import io.netty.handler.codec.bytes.ByteArrayDecoder; import io.netty.handler.codec.bytes.ByteArrayEncoder; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; import org.springframework.stereotype.Component; @Component public class SocketInitializer extends ChannelInitializer{ @Override protected void initChannel(SocketChannel socketChannel) throws Exception { ChannelPipeline pipeline = socketChannel.pipeline(); // // 添加对byte数组的编解码,netty提供了很多编解码器,你们可以根据需要选择 // pipeline.addLast(new ByteArrayDecoder()); // pipeline.addLast(new ByteArrayEncoder()); //添加一个基于行的解码器 pipeline.addLast(new LineBasedFrameDecoder(2048)); pipeline.addLast(new StringDecoder()); pipeline.addLast(new StringEncoder()); // 添加上自己的处理器 pipeline.addLast(new NettyServiceHandler()); } }
NettyServer
package server.netty;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
@Component
@Slf4j
public class NettyServer {
private final static Logger logger = LoggerFactory.getLogger(NettyServer.class);
@Resource
private SocketInitializer socketInitializer;
@Getter
private ServerBootstrap serverBootstrap;
/**
* netty服务监听端口
*/
@Value("${netty.port:6666}")
private int port;
/**
* 主线程组数量
*/
@Value("${netty.bossThread:1}")
private int bossThread;
/**
* 启动netty服务器
*/
public void start() {
this.init();
this.serverBootstrap.bind(this.port);
logger.info("Netty started on port: {} (TCP) with boss thread {}", this.port, this.bossThread);
}
/**
* 初始化netty配置
*/
private void init() {
NioEventLoopGroup bossGroup = new NioEventLoopGroup(this.bossThread);
NioEventLoopGroup workerGroup = new NioEventLoopGroup();
this.serverBootstrap = new ServerBootstrap();
this.serverBootstrap.group(bossGroup, workerGroup) // 两个线程组加入进来
.channel(NioServerSocketChannel.class) // 配置为nio类型
.option(ChannelOption.SO_BACKLOG, 128) //设置线程队列等待连接个数
.childOption(ChannelOption.SO_KEEPALIVE, true)
.childHandler(this.socketInitializer); // 加入自己的初始化器
}
}
NettyStartListener
package server.netty;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
/**
* 监听Spring容器启动完成,完成后启动Netty服务器
* @author Gjing
**/
@Component
public class NettyStartListener implements ApplicationRunner {
@Resource
private NettyServer nettyServer;
@Override
public void run(ApplicationArguments args) throws Exception {
this.nettyServer.start();
}
}
application.yml
server: port: 8000 netty: port: 6666 bossThread: 1

Client1
package client;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Client1 {
public static void main(String[] args) {
SpringApplication.run(Client1.class, args);
}
}
NettyClientHandler
package client.netty; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; public class NettyClientHandler extends SimpleChannelInboundHandler{ public void channelRead0(ChannelHandlerContext channelHandlerContext, String msg) { System.out.println("收到服务端消息:" + channelHandlerContext.channel().remoteAddress() + "的消息:" + msg); } public void exceptionCaught(ChannelHandlerContext channelHandlerContext, Throwable throwable) throws Exception { channelHandlerContext.close(); } }
SocketInitializer
package client.netty; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.LineBasedFrameDecoder; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; import org.springframework.stereotype.Component; @Component public class SocketInitializer extends ChannelInitializer{ @Override protected void initChannel(SocketChannel socketChannel) throws Exception { ChannelPipeline pipeline = socketChannel.pipeline(); pipeline.addLast(new LineBasedFrameDecoder(2048)); pipeline.addLast(new StringDecoder()); pipeline.addLast(new StringEncoder()); pipeline.addLast(new NettyClientHandler()); //加入自己的处理器 } }
NettyClient
package client.netty;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
@Component
@Slf4j
public class NettyClient {
private final static Logger logger = LoggerFactory.getLogger(NettyClient.class);
@Resource
private SocketInitializer socketInitializer;
@Getter
private Bootstrap bootstrap;
@Getter
private Channel channel;
/**
* netty服务监听端口
*/
@Value("${netty.port:6666}")
private int port;
@Value("${netty.host:127.0.0.1}")
private String host;
/**
* 启动netty
*/
public void start() {
this.init();
this.channel = this.bootstrap.connect(host, port).channel();
logger.info("Netty connect on port: {}, the host {}, the channel {}", this.port, this.host, this.channel);
try {
InputStreamReader is = new InputStreamReader(System.in, StandardCharsets.UTF_8);
BufferedReader br = new BufferedReader(is);
while (true) {
System.out.println("输入:");
this.channel.writeAndFlush(br.readLine() + "\r\n");
}
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 初始化netty配置
*/
private void init() {
EventLoopGroup group = new NioEventLoopGroup();
this.bootstrap = new Bootstrap();
//设置线程组
bootstrap.group(group)
.channel(NioSocketChannel.class) //设置客户端的通道实现类型
.handler(this.socketInitializer);
}
}
NettyStartListener
package client.netty;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
@Component
public class NettyStartListener implements ApplicationRunner {
@Resource
private NettyClient nettyClient;
@Override
public void run(ApplicationArguments args) throws Exception {
this.nettyClient.start();
}
}
application.yml
server: port: 8001 netty: port: 6666 host: "127.0.0.1"
然后按照相同的方法创建client2

