netty4.0 Server和Client的通信

创建一个maven项目

添加Netty依赖


          
     
      io.netty
           
     
      netty-all
           
     
      4.1.16.Final

Server端开发

public class HelloServer {    public void start(int port) {        ServerBootstrap serverBootstrap = new ServerBootstrap();//注意和 client 的区别        EventLoopGroup boosGroup = new NioEventLoopGroup();        EventLoopGroup workerGroup = new NioEventLoopGroup();        serverBootstrap.group(boosGroup, workerGroup);        serverBootstrap.channel(NioServerSocketChannel.class);//注意和 client 端的区别，client 端是 NioSocketChannel        serverBootstrap.childHandler(new ChannelInitializer
    
     () {                    protected void initChannel(SocketChannel socketChannel) throws Exception {                        ChannelPipeline pipeline = socketChannel.pipeline();                        pipeline.addLast(new HelloServerInHandler());                    }                });        serverBootstrap.option(ChannelOption.SO_BACKLOG, 128);        serverBootstrap.childOption(ChannelOption.SO_KEEPALIVE, true);        try {            // 绑定端口，开始接收进来的连接            ChannelFuture f = serverBootstrap.bind(port).sync();            // 等待服务器  socket 关闭 。            // 在这个例子中，这不会发生，但你可以优雅地关闭你的服务器。            f.channel().closeFuture().sync();        } catch (InterruptedException e) {            e.printStackTrace();        } finally {            boosGroup.shutdownGracefully();            workerGroup.shutdownGracefully();        }    }    public static void main(String[] args) {        HelloServer helloServer = new HelloServer();        int port = 8080;        if (args.length > 0) {            port = Integer.parseInt(args[0]);        }        helloServer.start(port);    }}

server 消息处理

@ChannelHandler.Sharablepublic class HelloServerInHandler extends ChannelInboundHandlerAdapter {    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {        try{            ByteBuf inMsg = (ByteBuf) msg;            byte[] bytes = new byte[inMsg.readableBytes()];            inMsg.readBytes(bytes);            String inStr = new String(bytes);            System.out.println("client send msg: " + inStr);            String response = "i am ok!";            ByteBuf outMsg = ctx.alloc().buffer(4 * response.length());            outMsg.writeBytes(response.getBytes());            ctx.writeAndFlush(outMsg);        }finally {            ReferenceCountUtil.release(msg);        }    }    @Override    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {        super.channelReadComplete(ctx);        ctx.flush();    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {        super.exceptionCaught(ctx, cause);        ctx.close();    }}

client 开发

public class HelloClient {    public void connect(String host, int port) {        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();        Bootstrap bootstrap = new Bootstrap(); //注意和 server 的区别        bootstrap.group(eventLoopGroup);        bootstrap.channel(NioSocketChannel.class);//注意和 server 端的区别，server 端是 NioServerSocketChannel        bootstrap.handler(new ChannelInitializer
    
     () {            protected void initChannel(SocketChannel socketChannel) throws Exception {                ChannelPipeline pipeline = socketChannel.pipeline();                pipeline.addLast(new HelloClientIntHandler());            }        });        bootstrap.option(ChannelOption.SO_KEEPALIVE, true);        try {            // Start the client.            ChannelFuture future = bootstrap.connect(host, port).sync();            // 等待服务器  socket 关闭 。            future.channel().closeFuture().sync();        } catch (InterruptedException e) {            e.printStackTrace();        } finally {            eventLoopGroup.shutdownGracefully();        }    }    public static void main(String[] args) {        HelloClient client = new HelloClient();        client.connect("127.0.0.1", 8080);    }}

client 消息处理

public class HelloClientIntHandler extends ChannelInboundHandlerAdapter {    // 连接成功后，向server发送消息    @Override    public void channelActive(ChannelHandlerContext ctx) throws Exception {        System.out.println("connected server. start send msg.");        String msg = "r u ok?";        ByteBuf encoded = ctx.alloc().buffer(4 * msg.length());        encoded.writeBytes(msg.getBytes());        ctx.writeAndFlush(encoded);    }    // 接收server端的消息，并打印出来    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {        try {            ByteBuf result = (ByteBuf) msg;            byte[] serverMsg = new byte[result.readableBytes()];            result.readBytes(serverMsg);            System.out.println("Server said:" + new String(serverMsg));        } finally {            ReferenceCountUtil.release(msg);        }    }}