Netty Client和Server端实现

public class Server {

    public static void run(int port) {
        /**Netty创建ServerSocketChannel,默认SelectionKey.OP_ACCEPT*/
        EventLoopGroup boss = new NioEventLoopGroup();
        EventLoopGroup worker = new NioEventLoopGroup();
        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(boss, worker)
                     .channel(NioServerSocketChannel.class)                // 设置Channel Type
                     .option(ChannelOption.SO_BACKLOG, 1024)            // 设置Channel属性
                     .childHandler(new ChannelInitializer<SocketChannel>() {

                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();
                            pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
                            pipeline.addLast("frameEncoder", new LengthFieldPrepender(4));
                            pipeline.addLast("decoder", new StringDecoder(CharsetUtil.UTF_8));
                            pipeline.addLast("encoder", new StringEncoder(CharsetUtil.UTF_8));
                            pipeline.addLast(new SimpleChannelHandler());
                        }
                    });            
            /**服务器端绑定监听端口并对Channel进行初始化
             * 1-ChannelConfig由ChannelOption初始化
             * 2-ChannelPipeline(默认DefaultChannelPipeline)添加ChannelHandler
             * 3-注册Channel并添加监听器ChannelFutureListener.CLOSE_ON_FAILURE
             * 以异步的方式等待上述操作的完成
             * */
            ChannelFuture channelFuture = bootstrap.bind(port).sync();
            if (channelFuture.isDone()) {
                System.out.println(String.format("server bind port %s sucess", port));
            }
            /**CloseFuture异步方式关闭*/
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            boss.shutdownGracefully();
            worker.shutdownGracefully();
        }
    }

    public static void main(String []args) {
        Server.run(8080);
    }
}

public class SimpleChannelHandler implements ChannelInboundHandler {

    private static final Gson GSON = new GsonBuilder().create();
    
    /**
     * the method called when new connect come
     * */
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        System.out.println(String.format("last channel handler [%s] add", ctx.pipeline().last().getClass().getSimpleName()));
    }

    /**
     * the method called when client close connect 
     * */
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        ctx.disconnect(ctx.newPromise());
        ctx.close();
    }

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

    /**
     * register port for connect channel
     * */
    public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
        String connect = ctx.channel().remoteAddress().toString().substring(1);
        System.out.println(String.format("remote connecter address %s", connect));
    }

    @Override
    public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
        
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        Request req = GSON.fromJson(String.valueOf(msg), Request.class);
        String json = GSON.toJson(new Response(String.format("server get client status [%s]", req.getStatus()), new Random().nextInt(10)));
        ctx.write(json);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        
    }

    @Override
    public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
        
    }

}