007-核心技术-netty-基于netty的群聊系统

一、基于netty群聊

服务器端

package com.github.bjlhx15.netty.demo.netty.groupchat;

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;

public class GroupChatServerHandler extends SimpleChannelInboundHandler<String> {

    //定义一个channel组。管理所有的channel
    //GlobalEventExecutor.INSTANCE是全局的事件执行器，是一个单例
    private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    //handlerAdded 表示连接建立，一旦连接，第一个被执行
//    当前的channel加入到 channelgroup
    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
//        将该客户加入聊天的信息推送到其他所有客户端
        // 该方法会将 channelGroup中所有的channel遍历，并发送消息，不需要自己遍历
        channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 加入聊天
");
        channelGroup.add(channel);
    }

    //断开连接
    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 离开了
");
//        channelGroup.remove()//不需要执行这里，这个方法会触发channelGroup 删除这个channel
    }

    //    表示channel处于活动状态
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + " 上线了");
    }

    //    表示channel处于不活动状态
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + " 离线了");
    }

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

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

服务器端Handler

package com.github.bjlhx15.netty.demo.netty.groupchat;

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;

public class GroupChatServerHandler extends SimpleChannelInboundHandler<String> {

    //定义一个channel组。管理所有的channel
    //GlobalEventExecutor.INSTANCE是全局的事件执行器，是一个单例
    private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    //handlerAdded 表示连接建立，一旦连接，第一个被执行
//    当前的channel加入到 channelgroup
    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
//        将该客户加入聊天的信息推送到其他所有客户端
        // 该方法会将 channelGroup中所有的channel遍历，并发送消息，不需要自己遍历
        channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 加入聊天
");
        channelGroup.add(channel);
    }

    //断开连接
    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 离开了
");
//        channelGroup.remove()//不需要执行这里，这个方法会触发channelGroup 删除这个channel
    }

    //    表示channel处于活动状态
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + " 上线了");
    }

    //    表示channel处于不活动状态
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + " 离线了");
    }

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

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

客户端

package com.github.bjlhx15.netty.demo.netty.groupchat;

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 InterruptedException {
        EventLoopGroup eventExecutors = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap()
                    .group(eventExecutors)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();
                            pipeline.addLast("decoder", new StringDecoder());
                            pipeline.addLast("encoder", new StringEncoder());
                            pipeline.addLast(new GroupChatClientHandler());//加入自己业务的handler
                        }
                    });
            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 s = scanner.nextLine();
                channel.writeAndFlush(s + "
");
            }
        } finally {
            eventExecutors.shutdownGracefully();
        }
    }

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

客户端Handler

package com.github.bjlhx15.netty.demo.netty.groupchat;

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

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

启动测试即可

如果有私聊，需要将ChannelGroup ，替换为Map<String,Channel>，key是用户ID，然后就能找到对应的Channel，在ChannelRead0时查找发送即可。