基于Netty的群聊系统

服务端:

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
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 GroupChatServer {

    private int port;

    public GroupChatServer(int port){
        this.port = port;
    }

    public void run() throws Exception {
        NioEventLoopGroup bossGroup = new NioEventLoopGroup(1);
        NioEventLoopGroup workerGroup = new NioEventLoopGroup();
        try {

            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .childHandler(new ChannelInitializer() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {

                            ChannelPipeline pipeline = socketChannel.pipeline();
                            pipeline.addLast("decorder", new StringDecoder());
                            pipeline.addLast("encoder", new StringEncoder());
                            pipeline.addLast(new GroupChatServerHandler());

                        }

                    });

            System.out.println("netty 服务器启动");
            ChannelFuture channelFuture = bootstrap.bind(port).sync();

            channelFuture.channel().closeFuture().sync();
        }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }


    }

    public static void main(String[] args) throws Exception {
        new GroupChatServer(7000).run();
    }
}

服务端Handler:

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;

import java.text.SimpleDateFormat;
import java.util.Date;

public class GroupChatServerHandler extends SimpleChannelInboundHandler {

    private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE );
    private static SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
       Channel channel = ctx.channel();
       channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + "加入聊天" + simpleDateFormat.format(new Date()) + "\no");
       channelGroup.add(channel);
    }

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + "离开了\n");
        System.out.println("channelGroup Size" + channelGroup.size());
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String s) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.forEach(ch ->{
            if(channel != ch){
                ch.writeAndFlush("[客户]" + channel.remoteAddress() + "发送消息" + s +"\n");
            }else{
                ch.writeAndFlush("[自己]发送了消息" + s + "\n");
            }
        });
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + "上线了");
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + "离线了");
    }

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

客户端:

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
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 java.util.Scanner;

public class GroupChatClient {
    private final String host;
    private final int port;

    public GroupChatClient(String host,int port){
        this.host = host;
        this.port = port;
    }

    public void run() throws Exception {
        NioEventLoopGroup group = new NioEventLoopGroup();

        try {

            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) {
                            ChannelPipeline pipeline = socketChannel.pipeline();
                            pipeline.addLast("decorder", new StringDecoder());
                            pipeline.addLast("encoder", new StringEncoder());
                            pipeline.addLast(new GroupChatClientHandler());
                        }
                    });
            ChannelFuture channelFuture = bootstrap.connect(host, port).sync();
            Channel channel = channelFuture.channel();
            System.out.println("----" + channel.localAddress() + "----");
            Scanner scanner = new Scanner(System.in);
            while(scanner.hasNextLine()){
                String msg = scanner.nextLine();
                channel.writeAndFlush(msg + "\r\n");
            }
        }finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        new GroupChatClient("127.0.0.1",7000).run();
    }
}

客户端handler:

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

public class GroupChatClientHandler extends SimpleChannelInboundHandler {
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, String s) throws Exception {
        System.out.println(s.trim());
    }
}

Github :https://github.com/WillLiaowh/nettyDemo