从零学Netty（七）Netty实现多人聊天室

￡神魔★判官ぃ 2022-12-15 03:51 208阅读 0赞

# 实例demo #

### 编写服务端 ###

/**
     * 服务端
     *
     * @author LionLi
     */
    public class GroupChatServer {
    
        private final int port;
    
        public GroupChatServer(int port) {
            this.port = port;
        }
    
        public void run() throws Exception {
    
            // boss组 使用一个线程接收和分发请求
            EventLoopGroup bossGroup = new NioEventLoopGroup(1);
            // worker工作组 默认线程数8 处理实际请求
            EventLoopGroup workerGroup = new NioEventLoopGroup();
    
            try {
                ServerBootstrap b = new ServerBootstrap();
                b.group(bossGroup, workerGroup)
                        // 主线程处理类
                        .channel(NioServerSocketChannel.class)
                        // 针对主线程的配置 分配线程最大数量 128
                        .option(ChannelOption.SO_BACKLOG, 128)
                        // 针对子线程的配置 保持长连接
                        .childOption(ChannelOption.SO_KEEPALIVE, true)
                        // 子线程处理类
                        .childHandler(new ChannelInitializer<SocketChannel>() {
                            @Override
                            protected void initChannel(SocketChannel ch) {
                                ChannelPipeline pipeline = ch.pipeline();
                                // 加入 编解码handler
                                pipeline.addLast("decoder", new StringDecoder());
                                pipeline.addLast("encoder", new StringEncoder());
                                // 加入自己的业务处理handler
                                pipeline.addLast(new GroupChatServerHandler());
                            }
                        });
    
                System.out.println("服务器正在监听......");
                ChannelFuture channelFuture = b.bind(port).sync();
    
                // 监听关闭
                channelFuture.channel().closeFuture().sync();
            } finally {
                bossGroup.shutdownGracefully();
                workerGroup.shutdownGracefully();
            }
    
        }
    
        public static void main(String[] args) throws Exception {
            new GroupChatServer(8088).run();
        }
    }

### 编写服务端业务处理器 ###

/**
     * 服务端业务处理器
     *
     * @author LionLi
     */
    public class GroupChatServerHandler extends SimpleChannelInboundHandler<String> {
    
        /**
         * 定义一个channle 组，管理所有的channel
         * GlobalEventExecutor.INSTANCE) 是全局的事件执行器，是一个单例
         * 内部使用ConcurrentHashMap管理,线程安全
         */
        private static final ChannelGroup CHANNEL_GROUP = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    
        /**
         * 初始化连接事件
         */
        @Override
        public void handlerAdded(ChannelHandlerContext ctx) {
            Channel channel = ctx.channel();
            CHANNEL_GROUP.add(channel);
        }
    
        /**
         * 连接断开事件
         */
        @Override
        public void handlerRemoved(ChannelHandlerContext ctx) {
            System.out.println("聊天室人数:" + CHANNEL_GROUP.size());
        }
    
        /**
         * 通道新增事件
         */
        @Override
        public void channelActive(ChannelHandlerContext ctx) {
            System.out.println(ctx.channel().remoteAddress() + " 上线了");
        }
    
        /**
         * 通道关闭事件
         */
        @Override
        public void channelInactive(ChannelHandlerContext ctx) {
            System.out.println(ctx.channel().remoteAddress() + " 离线了");
        }
    
        /**
         * 读取数据
         */
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, String msg) {
            CHANNEL_GROUP.writeAndFlush(msg);
        }
    
        /**
         * 异常事件
         */
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
            //关闭通道
            ctx.close();
        }
    }

### 编写客户端 ###

/**
     * 客户端
     *
     * @author LionLi
     */
    public class GroupChatClient {
    
        private final String host;
        private final int port;
        private final String username;
    
        public GroupChatClient(String host, int port, String username) {
            this.host = host;
            this.port = port;
            this.username = username;
        }
    
        public void run() throws Exception {
            EventLoopGroup group = new NioEventLoopGroup();
            try {
                Bootstrap bootstrap = new Bootstrap()
                        .group(group)
                        .channel(NioSocketChannel.class)
                        .handler(new ChannelInitializer<SocketChannel>() {
                            @Override
                            protected void initChannel(SocketChannel ch) {
                                ChannelPipeline pipeline = ch.pipeline();
                                //加入 编解码handler
                                pipeline.addLast("decoder", new StringDecoder());
                                pipeline.addLast("encoder", new StringEncoder());
                                //加入自定义的handler
                                pipeline.addLast(new GroupChatClientHandler());
                            }
                        });
    
                ChannelFuture channelFuture = bootstrap.connect(host, port).sync();
                Channel channel = channelFuture.channel();
    
                channel.writeAndFlush(username + " 上线了");
    
                //客户端需要输入信息，创建一个扫描器
                Scanner scanner = new Scanner(System.in);
                while (scanner.hasNextLine()) {
                    String msg = scanner.nextLine();
                    if ("exit".equals(msg)) {
                        channel.writeAndFlush(username + " 离开了");
                        break;
                    } else {
                        channel.writeAndFlush(username + ":" + msg);
                    }
                }
            } finally {
                group.shutdownGracefully();
            }
        }
    
        public static void main(String[] args) throws Exception {
            System.out.print("请输入用户名: ");
            Scanner scanner = new Scanner(System.in);
            String username = scanner.nextLine();
            new GroupChatClient("localhost", 8088, username).run();
        }
    }

### 编写客户端业务处理器 ###

/**
     * 客户端业务处理器
     *
     * @author LionLi
     */
    public class GroupChatClientHandler extends SimpleChannelInboundHandler<String> {
    
        /**
         * 读取数据
         */
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, String msg) {
            System.out.println(msg.trim());
        }
    }

# 测试 #

*  场景如下：
 *  启动服务端
 *  顺序启动客户端 群友ABC 并输入用户名
 *  分别打招呼
 *  倒序退出客户端 群友ABC

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70 2][]

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项目已上传到gitee

地址: [netty-demo][]

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[netty-demo]: https://gitee.com/JavaLionLi/LionLi-Labs/tree/master/netty-demo