Netty的入门-基础编程

Server端实现：

public class TimeServer {public void bind(int port) throws Exception {// 配置服务端的NIO线程组EventLoopGroup bossGroup = new NioEventLoopGroup(); // 用于服务端接受客户端的连接EventLoopGroup workerGroup = new NioEventLoopGroup(); // 用于进行SocketChannel的网络读写try {// 服务端启动辅助类ServerBootstrap b = new ServerBootstrap();b.group(bossGroup, workerGroup) // 两个NIO线程组.channel(NioServerSocketChannel.class) // 设置要创建的Channel.option(ChannelOption.SO_BACKLOG, 1024) // 设置TCP参数.childOption(ChannelOption.SO_KEEPALIVE, true) // 保持心跳.childHandler(new ChannelInitializer<SocketChannel>() {@Overrideprotected void initChannel(SocketChannel socketChannel) throws Exception {socketChannel.pipeline().addLast(new TimeServerHandler());}}); // 绑定I/O事件的处理类，用于处理请求// 绑定端口，同步等待成功ChannelFuture f = b.bind(port).sync(); // 只要用于异步操作的通知回调// 等待服务端监听端口关闭f.channel().closeFuture().sync(); // 等待服务端链路关闭之后退出} catch (Exception e) {e.printStackTrace();} finally {// 优雅退出bossGroup.shutdownGracefully();workerGroup.shutdownGracefully();}}private class TimeServerHandler extends ChannelInboundHandlerAdapter  {@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg)throws Exception {try {ByteBuf buf = (ByteBuf) msg;byte[] req = new byte[buf.readableBytes()];buf.readBytes(req);String body = new String(req, "UTF-8");System.out.println("The time server receive order ： " + body);String currentTime = "QUERY TIME ORDER".equals(body) ? new Date(System.currentTimeMillis()).toString() : "Bad Order";ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());ctx.write(resp); // 写到消息队列而不是写到SocketChannel中} finally {ReferenceCountUtil.release(msg);}}@Overridepublic void channelReadComplete(ChannelHandlerContext ctx)throws Exception {// 将消息发送队列中的消息写入到SocketChannel中发送给对方// 从性能角度考虑，为了防止频繁的唤醒selector进行消息发送ctx.flush();}@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)throws Exception {ctx.close();}}public static void main(String[] args) {try {new TimeServer().bind(1234);} catch (Exception e) {e.printStackTrace();}}

}

客户端实现：

public class TimeClient {public void connect(int port, String host) {// 配置客户端NIO线程组EventLoopGroup group = new NioEventLoopGroup();try {Bootstrap b = new Bootstrap();b.group(group).channel(NioSocketChannel.class).handler(new ChannelInitializer<SocketChannel>() {@Overrideprotected void initChannel(SocketChannel ch)throws Exception {ch.pipeline().addLast(new TimeClientHandler());}});// 发起异步连接操作ChannelFuture f = b.connect(host, port).sync();f.channel().closeFuture().sync();} catch (Exception e) {e.printStackTrace();} finally {// 优雅退出，释放NIO线程组group.shutdownGracefully();}}public class TimeClientHandler extends ChannelInboundHandlerAdapter  {private final ByteBuf firstMessage;public TimeClientHandler() {super();byte[] req = "QUERY TIME ORDER".getBytes();firstMessage = Unpooled.buffer(req.length);firstMessage.writeBytes(req);}@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)throws Exception {ctx.close();}@Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception {ctx.writeAndFlush(firstMessage);}@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg)throws Exception {ByteBuf buf = (ByteBuf) msg;byte[] req = new byte[buf.readableBytes()];buf.readBytes(req);String body = new String(req, "UTF-8");System.out.println("Now is " + body);}}public static void main(String[] args) {new TimeClient().connect(1234, "127.0.0.1");}}