客户端

EchoClient

public class EchoClient {
    private final int port;
    private final String host;
    public EchoClient(int port, String host) {
        this.port = port;
        this.host = host;
    }
    public void start() throws InterruptedException {
        //线程组
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            //客户端启动必须
            final Bootstrap b = new Bootstrap();;
            //将线程组传入
            b.group(group)
                    //指定使用NIO进行网络传输
                    .channel(NioSocketChannel.class)
                    //配置要连接服务器的ip地址和端口
                    .remoteAddress(new InetSocketAddress(host,port))
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new EchoClientHandler());
                        }
                    });
            // 异步连接服务器，阻塞直到连接完成
            ChannelFuture f = b.connect().sync();
            f.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully().sync();
        }
    }
    public static void main(String[] args) throws InterruptedException {
        new EchoClient(9999,"127.0.0.1").start();
    }
}

EchoClientHandler

public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
    //读取到网络数据后进行业务处理
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg) throws Exception {
        System.out.println("client Accept"+msg.toString(CharsetUtil.UTF_8));
        //ctx.close();
        ctx.close();
    }
    //channel活跃后，做业务处理
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush(Unpooled.copiedBuffer(
                "Hello,Netty",CharsetUtil.UTF_8));
    }
}