基于Netty的简易网络编程demo
服务器端
package me.jar.netty.simple; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelOption; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioServerSocketChannel; /** * @Description * @Date 2021/2/19-21:19 */ public class NettyServer { public static void main(String[] args) throws InterruptedException { // 创建bossGroup和workerGroup // 创建两个线程组 bossGroup和workerGroup,bossGroup只负责处理连接请求,workerGroup负责客户端业务处理。两个都是无限循环 EventLoopGroup bossGroup = new NioEventLoopGroup(1); EventLoopGroup workerGroup = new NioEventLoopGroup(); try { // 创建服务端的启动对象,配置参数 ServerBootstrap bootstrap = new ServerBootstrap(); // 对启动对象进行设置 bootstrap.group(bossGroup, workerGroup) // 设置两个线程组 .channel(NioServerSocketChannel.class) // 使用NioServerSocketChannel作为服务器的通道实现 .option(ChannelOption.SO_BACKLOG, 128) // 设置线程队列等待连接个数 .childOption(ChannelOption.SO_KEEPALIVE, true) // 设置保持活动连接状态 .childHandler(new ChannelInitializer<SocketChannel>() { // 创建一个通道初始化对象(匿名对象) // 给pipeline设置处理器 @Override protected void initChannel(SocketChannel ch) { ch.pipeline().addLast(new NettyServerHandler()); } }); // 给workerGroup的EventLoop对应的管道设置处理器 System.out.println("服务器准备完成..."); // 绑定一个端口并且同步,生成一个ChannelFuture对象。启动服务器,并绑定端口 ChannelFuture cf = bootstrap.bind(6666).sync(); // 对关闭通道进行监听 cf.channel().closeFuture().sync(); } finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } }
package me.jar.netty.simple; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import io.netty.util.CharsetUtil; /** * @Description 1.自定义一个handler,需要继承Netty规定好的某个HandlerAdapter(规范) * 这时我们自定义的Handler,才能称为一个Handler * @Date 2021/2/19-21:57 */ public class NettyServerHandler extends ChannelInboundHandlerAdapter { // 读取数据方法(这里可以读取客户端发送的消息) // ChannelHandlerContext ctx:上下文对象,含有管道pipeline,通道channel,地址等 // Object msg:就是客户端发送的数据,默认Object @Override public void channelRead(ChannelHandlerContext ctx, Object msg) { // 将msg转成一个ByteBuf。ByteBuf是Netty提供的,不是NIO的ByteBuffer ByteBuf byteBuf = (ByteBuf) msg; System.out.println("客户端发送的消息是:" + byteBuf.toString(CharsetUtil.UTF_8)); System.out.println("客户端地址:" + ctx.channel().remoteAddress()); } // 数据读取完毕 @Override public void channelReadComplete(ChannelHandlerContext ctx) { // writeAndFlush是write + flush // 将数据写入到缓存,并刷新。一般的,对发送的数据进行编码 ctx.writeAndFlush(Unpooled.copiedBuffer("hello,客户端~", CharsetUtil.UTF_8)); } // 处理异常,一般是需要关闭通道 @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); ctx.close(); } }
客户端
package me.jar.netty.simple; import io.netty.bootstrap.Bootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelInitializer; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioSocketChannel; /** * @Description * @Date 2021/2/19-22:11 */ public class NettyClient { public static void main(String[] args) throws InterruptedException { // 客户端需要一个事件循环组 EventLoopGroup eventExecutors = new NioEventLoopGroup(); try { // 创建客户端启动对象 Bootstrap bootstrap = new Bootstrap(); // 设置相关参数 bootstrap.group(eventExecutors) // 设置线程组 .channel(NioSocketChannel.class) // 设置客户端通道的实现类(反射) .handler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel ch) { ch.pipeline().addLast(new NettyClientHandler()); // 加入自己的处理器 } }); System.out.println("客户端准备完毕..."); // 启动客户端去连接服务器端 ChannelFuture cf = bootstrap.connect("127.0.0.1", 6666).sync(); // 对关闭通道进行监听 cf.channel().closeFuture().sync(); } finally { eventExecutors.shutdownGracefully(); } } }
package me.jar.netty.simple; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import io.netty.util.CharsetUtil; /** * @Description * @Date 2021/2/19-22:17 */ public class NettyClientHandler extends ChannelInboundHandlerAdapter { // 当通道就绪就会触发该方法 @Override public void channelActive(ChannelHandlerContext ctx) { ctx.writeAndFlush(Unpooled.copiedBuffer("hello,服务器", CharsetUtil.UTF_8)); } // 当通道有读取事件时,就会触发该方法 @Override public void channelRead(ChannelHandlerContext ctx, Object msg) { ByteBuf byteBuf = (ByteBuf) msg; System.out.println("服务器回复的消息->" + byteBuf.toString(CharsetUtil.UTF_8)); System.out.println("服务器的地址->" + ctx.channel().remoteAddress()); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); ctx.close(); } }