群聊系统

Servier

public class GroupChatServer {
    private int port;
    public GroupChatServer(int port) {
        this.port = port;
    }
    //run方法处理客户端请求
    public void run() throws InterruptedException {
        //创建两个线程组
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            //获取pipeline
                            ChannelPipeline pipeline = ch.pipeline();
                            //向pipeline中加入一个解码器
                            pipeline.addLast("decoder", new StringDecoder());
                            //加入编码器
                            pipeline.addLast("encoder", new StringEncoder());
                            //自定义handler
                            pipeline.addLast(new GroupChatServerHandler());
                        }
                    });
            System.out.println("netty 服务器启动了 ");
            ChannelFuture channelFuture = serverBootstrap.bind(port).sync();
            //监听关闭
            channelFuture.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
    public static void main(String[] args) throws InterruptedException {
        new GroupChatServer(7000).run();
    }
}

ServerHandler

public class GroupChatServerHandler extends SimpleChannelInboundHandler<String> {
    //定义一个Channel组 管理所有的Channel
    //GlobalEventExecutor.INSTANCE是一个全局的事件执行器，是一个单列
    private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    //处理时间
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    //表示连接建立之后调用的方法，一但连接第一个被执行
    //将当前channel加入到channelGroup
    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
        //将客户加入聊天的信息推送给其他在线的客户端
        //该方法会将channelGroup中所有的Channel遍历并发送消息
        channelGroup.writeAndFlush("客户端：" + channel.remoteAddress() + "加入聊天\n");
        channelGroup.add(channel);
    }
    //表示断开连接被触发，并把当前channel自动从ChannelGroup中移除
    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.writeAndFlush("客户端：" + channel.remoteAddress() + "退出聊天\n");
    }
    //表示channel 处于活动状态，提示用户上线
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + "--上线了");
    }
    //channel 处于不活动状态，提示用户离线
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + "--离线了");
    }
    //读取数据并转发给当前在线的用户
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        //获取到当前Channel
        Channel channel = ctx.channel();
        //分别处理，不能给自己转发消息，根据不同的用户回复不同的消息
        channelGroup.forEach(ch -> {
            if (channel != ch) { //不是当前的channel，直接转发消息
                ch.writeAndFlush("客户" + channel.remoteAddress() + "：" + msg + "\n");
            } else { //回显自己发送的消息
                ch.writeAndFlush("自己发送了：" + msg + "\n");
            }
        });
    }
    //异常处理
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
    }
}

Client

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();
            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());
                        }
                    });
            ChannelFuture channelFuture = bootstrap.connect(HOST, PORT).sync();
            Channel channel = channelFuture.channel();
            System.out.println(channel.localAddress() + "准备好了~~~~~~~~~");
            //客户端需要输入信息
            Scanner scanner = new Scanner(System.in);
            while (scanner.hasNextLine()) {
                String msg = scanner.nextLine();
                //通过Channel到服务器端
                channel.writeAndFlush(msg + "\r\n");
            }
        } finally {
            eventExecutors.shutdownGracefully();
        }
    }
    public static void main(String[] args) throws InterruptedException {
        new GroupChatClient("127.0.0.1", 7000).run();
    }
}

ClientHandler

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