从入门到超神进阶的Netty群聊系统从入门到超神进阶的Netty群聊系

服务端
客户端

服务端服务端一样的需要创建BossGroup 和 WorkGroup , 然后使用ServerBootStrap 来配置Netty和启动Netty。

public class NettyGroupChatServer {public static void main(String[] args) {new NettyGroupChatServer().start(); }//监听public void start(){//循环组NioEventLoopGroup bossGroup = new NioEventLoopGroup(); NioEventLoopGroup workGroup = new NioEventLoopGroup(); //启动引导ServerBootstrap bootstrap = new ServerBootstrap(); //Netty配置bootstrap.group(bossGroup,workGroup).option(ChannelOption.SO_BACKLOG,32).childOption(ChannelOption.SO_KEEPALIVE,true).channel(NioServerSocketChannel.class).childHandler(new ChannelInitializer() {@Overrideprotected void initChannel(SocketChannel channel) throws Exception {//解码器channel.pipeline().addLast("decoder", new StringDecoder()); //编码器channel.pipeline().addLast("encoder",new StringEncoder()); //处理器channel.pipeline().addLast("nettyGroupChatHandler",new NettyGroupChatServerHandler()); }}); try {//启动服务ChannelFuture future = bootstrap.bind(new InetSocketAddress("127.0.0.1", 8888)).sync(); future.channel().closeFuture().sync(); } catch (InterruptedException e) {e.printStackTrace(); }finally {//关闭资源bossGroup.shutdownGracefully(); workGroup.shutdownGracefully(); }}}

服务端处理器我们通过继承 SimpleChannelInboundHandler 入站Handler来处理消息。
其中提供了几个方法

channelRead0 ()：读取消息
handlerRemoved ()：客户端断开
handlerAdded ()：客户端建立连接
exceptionCaught ()：出现异常

具体代码如下

public class NettyGroupChatServerHandler extends SimpleChannelInboundHandler {//把所有客户端的channel保存起来private static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); private static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); @Overrideprotected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {String message = dateFormat.format(new Date())+":%s:"+msg; //消息转发给所有的客户端channels.forEach(channel -> {if(channel == ctx.channel()){String sendMsg = String.format(message, "我"); channel.writeAndFlush(sendMsg); System.out.println(sendMsg); }else{String sendMsg = String.format(message, ctx.channel().remoteAddress()); channel.writeAndFlush(sendMsg); System.out.println(sendMsg); }}); }//断开连接 , 把消息广播给其他客户端@Overridepublic void handlerRemoved(ChannelHandlerContext ctx) throws Exception {String message = dateFormat.format(new Date())+":"+ctx.channel().remoteAddress()+":断开连接"; channels.writeAndFlush(message); System.out.println(message); }//建立连接@Overridepublic void handlerAdded(ChannelHandlerContext ctx) throws Exception {String message = dateFormat.format(new Date())+":"+ctx.channel().remoteAddress()+":加入聊天室"; //自动把消息广播给其客户端channels.writeAndFlush(message); //客户端加入组channels.add(ctx.channel()); System.out.println(message); }//出现异常@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {ctx.channel().close(); }//客户端退出@Overridepublic void channelInactive(ChannelHandlerContext ctx) throws Exception {String message = dateFormat.format(new Date())+":"+ctx.channel().remoteAddress()+":退出聊天室"; System.out.println(message); }//客户端出于活动@Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception {String message = dateFormat.format(new Date())+":"+ctx.channel().remoteAddress()+":上线啦"; System.out.println(message); }}

客户端客户端需要创建一个循环事件组，然后通过BootStrap去启动,然后扫描键盘输入作为数据源来把信息发送给服务端

public class NettyGroupChatClient {public static void main(String[] args) {new NettyGroupChatClient().start(); }public void start(){NioEventLoopGroup eventLoopGroup = new NioEventLoopGroup(); Bootstrap bootstrap = new Bootstrap(); bootstrap.group(eventLoopGroup).channel(NioSocketChannel.class).handler(new ChannelInitializer() {@Overrideprotected void initChannel(SocketChannel channel) throws Exception {//解码器channel.pipeline().addLast("decoder", new StringDecoder()); //编码器channel.pipeline().addLast("encoder",new StringEncoder()); //处理器channel.pipeline().addLast("nettyGroupChatClientHandler",new NettyGroupChatClientHandler()); }}); try {ChannelFuture future = bootstrap.connect(new InetSocketAddress("127.0.0.1", 8888)).sync(); //通道Channel channel = future.channel(); //扫描键盘输入Scanner scanner = new Scanner(System.in); while(scanner.hasNextLine()){String message = scanner.nextLine(); //发送数据channel.writeAndFlush(message); }} catch (InterruptedException e) {}finally {eventLoopGroup.shutdownGracefully(); }}}

对于处理器只需要接收服务端转发过来的消息即可

public class NettyGroupChatClientHandler extends SimpleChannelInboundHandler {@Overrideprotected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {System.out.println(msg); }}

启动服务端和多个客户端，效果如下