Netty通信中如何实现高效的数据传输？

import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.*; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioServerSocketChannel; import io.netty.channel.socket.nio.NioSocketChannel; public class NettyServer { public static void main(String[] args) throws Exception { //创建BossGroup 和 WorkerGroup //说明 //1. 创建两个线程组 bossGroup 和 workerGroup //2. bossGroup 只是处理连接请求 , 真正的和客户端业务处理，会交给 workerGroup完成 //3. 两个都是无限循环 //4. bossGroup 和 workerGroup 含有的子线程(NioEventLoop)的个数 // 默认实际 cpu核数 * 2 EventLoopGroup bossGroup = new NioEventLoopGroup(1); EventLoopGroup workerGroup = new NioEventLoopGroup(); //8 try { //创建服务器端的启动对象，配置参数 ServerBootstrap bootstrap = new ServerBootstrap(); //使用链式编程来进行设置 bootstrap.group(bossGroup, workerGroup) //设置两个线程组 .channel(NioServerSocketChannel.class) //使用NioSocketChannel 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 // .handler(null) // 该 handler对应 bossGroup , childHandler 对应 workerGroup .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) throws Exception { System.out.println("客户socketchannel hashcode=" + ch.hashCode()); //可以使用一个集合管理 SocketChannel， 再推送消息时，可以将业务加入到各个channel 对应的 NIOEventLoop 的 taskQueue 或者 scheduleTaskQueue ch.pipeline().addLast(new NettyServerHandler()); } }); // 给我们的workerGroup 的 EventLoop 对应的管道设置处理器 System.out.println(".....服务器 is ready..."); //绑定一个端口并且同步生成了一个 ChannelFuture 对象（也就是立马返回这样一个对象） //启动服务器(并绑定端口) ChannelFuture cf = bootstrap.bind(6668).sync(); //给cf 注册监听器，监控我们关心的事件 cf.addListener(new ChannelFutureListener() { @Override public void operationComplete(ChannelFuture future) throws Exception { if (cf.isSuccess()) { System.out.println("监听端口 6668 成功"); } else { System.out.println("监听端口 6668 失败"); } } }); //对关闭通道事件 进行监听 cf.channel().closeFuture().sync(); }finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } }

import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import io.netty.channel.ChannelPipeline; import io.netty.util.CharsetUtil; import java.util.concurrent.TimeUnit; /* 说明 1. 我们自定义一个Handler 需要继承netty 规定好的某个HandlerAdapter(规范) 2. 这时我们自定义一个Handler , 才能称为一个handler */ public class NettyServerHandler extends ChannelInboundHandlerAdapter { //读取数据事件(这里我们可以读取客户端发送的消息) /* 1. ChannelHandlerContext ctx:上下文对象, 含有 管道pipeline , 通道channel, 地址 2. Object msg: 就是客户端发送的数据 默认Object */ @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { System.out.println("服务器读取线程 " + Thread.currentThread().getName() + " channle =" + ctx.channel()); System.out.println("server ctx =" + ctx); System.out.println("看看channel 和 pipeline的关系"); Channel channel = ctx.channel(); ChannelPipeline pipeline = ctx.pipeline(); //本质是一个双向链表 //将 msg 转成一个 ByteBuf //ByteBuf 是 Netty 提供的，不是 NIO 的 ByteBuffer. ByteBuf buf = (ByteBuf) msg; System.out.println("客户端发送消息是:" + buf.toString(CharsetUtil.UTF_8)); System.out.println("客户端地址:" + channel.remoteAddress()); } //数据读取完毕 @Override public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { //writeAndFlush 是 write + flush //将数据写入到缓存，并刷新 //一般讲，我们对这个发送的数据进行编码 ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端~(>^ω^<)喵1", CharsetUtil.UTF_8)); } //发生异常后, 一般是需要关闭通道 @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { ctx.close(); } }

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; public class NettyClient { public static void main(String[] args) throws Exception { //客户端需要一个事件循环组 EventLoopGroup group = new NioEventLoopGroup(); try { //创建客户端启动对象 //注意客户端使用的不是 ServerBootstrap 而是 Bootstrap Bootstrap bootstrap = new Bootstrap(); //设置相关参数 bootstrap.group(group) //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) throws Exception { ch.pipeline().addLast(new NettyClientHandler()); //加入自己的处理器 } }); System.out.println("客户端 ok.."); //启动客户端去连接服务器端 //关于 ChannelFuture 要分析，涉及到netty的异步模型 ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 6668).sync(); //对关闭通道事件 进行监听 channelFuture.channel().closeFuture().sync(); }finally { group.shutdownGracefully(); } } }

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; public class NettyClientHandler extends ChannelInboundHandlerAdapter { //当通道就绪就会触发该方法 @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { System.out.println("client " + ctx); ctx.writeAndFlush(Unpooled.copiedBuffer("hello, server: (>^ω^<)喵", CharsetUtil.UTF_8)); } //当通道有读取事件时，会触发 @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; System.out.println("服务器回复的消息:" + buf.toString(CharsetUtil.UTF_8)); System.out.println("服务器的地址： "+ ctx.channel().remoteAddress()); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } }

import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.*; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioServerSocketChannel; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; public class GroupChatServer { private int port; //监听端口 public GroupChatServer(int port) { this.port = port; } //编写run方法，处理客户端的请求 public void run() throws Exception{ //创建两个线程组 EventLoopGroup bossGroup = new NioEventLoopGroup(1); EventLoopGroup workerGroup = new NioEventLoopGroup(); //8个NioEventLoop try { ServerBootstrap b = new ServerBootstrap(); b.group(bossGroup, workerGroup) .channel(NioServerSocketChannel.class) .option(ChannelOption.SO_BACKLOG, 128) .childOption(ChannelOption.SO_KEEPALIVE, true) .childHandler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel ch) throws Exception { //获取到pipeline ChannelPipeline pipeline = ch.pipeline(); //向pipeline加入解码器 pipeline.addLast("decoder", new StringDecoder()); //向pipeline加入编码器 pipeline.addLast("encoder", new StringEncoder()); //加入自己的业务处理handler pipeline.addLast(new GroupChatServerHandler()); } }); System.out.println("netty 服务器启动"); ChannelFuture channelFuture = b.bind(port).sync(); //监听关闭 channelFuture.channel().closeFuture().sync(); }finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } public static void main(String[] args) throws Exception { new GroupChatServer(7000).run(); } }

import io.netty.channel.Channel; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.channel.group.ChannelGroup; import io.netty.channel.group.DefaultChannelGroup; import io.netty.util.concurrent.GlobalEventExecutor; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class GroupChatServerHandler extends SimpleChannelInboundHandler<String> { //这样写还要自己遍历Channel //public static List<Channel> channels = new ArrayList<Channel>(); //使用一个hashmap 管理私聊（私聊本案例并未实现，只是提供个思路） //public static Map<String, Channel> channels = new HashMap<String,Channel>(); //定义一个channle 组，管理所有的channel //GlobalEventExecutor.INSTANCE) 是全局的事件执行器，是一个单例 private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //handlerAdded 表示连接建立，一旦连接，第一个被执行 //将当前channel 加入到 channelGroup @Override public void handlerAdded(ChannelHandlerContext ctx) throws Exception { Channel channel = ctx.channel(); //将该客户加入聊天的信息推送给其它在线的客户端 //该方法会将 channelGroup 中所有的channel 遍历，并发送消息，我们不需要自己遍历 channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 加入聊天" + sdf.format(new java.util.Date()) + " \n"); channelGroup.add(channel); //私聊如何实现 // channels.put（"userid100",channel）; } //断开连接, 将xx客户离开信息推送给当前在线的客户 @Override public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { Channel channel = ctx.channel(); channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 离开了\n"); System.out.println("channelGroup size" + channelGroup.size()); } //表示channel 处于活动状态, 提示 xx上线 @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { //这个是给服务端看的，客户端上面已经提示xxx加入群聊了 System.out.println(ctx.channel().remoteAddress() + " 上线了~"); } //表示channel 处于不活动状态, 提示 xx离线了 @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { System.out.println(ctx.channel().remoteAddress() + " 离线了~"); } //读取数据，转发给在线的每一个客户端 @Override protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception { //获取到当前channel Channel channel = ctx.channel(); //这时我们遍历channelGroup, 根据不同的情况，回送不同的消息 channelGroup.forEach(ch -> { if(channel != ch) { //不是当前的channel,转发消息 ch.writeAndFlush("[客户]" + channel.remoteAddress() + " 发送了消息" + msg + "\n"); }else {//回显自己发送的消息给自己 ch.writeAndFlush("[自己]发送了消息" + msg + "\n"); } }); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { //关闭通道 ctx.close(); } }

import io.netty.bootstrap.Bootstrap; import io.netty.channel.*; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioSocketChannel; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; import java.util.Scanner; public class GroupChatClient { //属性 private final String host; private final int port; public GroupChatClient(String host, int port) { this.host = host; this.port = port; } public void run() throws Exception{ EventLoopGroup group = new NioEventLoopGroup(); try { Bootstrap bootstrap = new Bootstrap() .group(group) .channel(NioSocketChannel.class) .handler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel ch) throws Exception { //得到pipeline ChannelPipeline pipeline = ch.pipeline(); //加入相关handler pipeline.addLast("decoder", new StringDecoder()); pipeline.addLast("encoder", new StringEncoder()); //加入自定义的handler pipeline.addLast(new GroupChatClientHandler()); } }); ChannelFuture channelFuture = bootstrap.connect(host, port).sync(); //得到channel Channel channel = channelFuture.channel(); System.out.println("-------" + channel.localAddress()+ "--------"); //客户端需要输入信息，创建一个扫描器 Scanner scanner = new Scanner(System.in); while (scanner.hasNextLine()) { String msg = scanner.nextLine(); //通过channel 发送到服务器端 channel.writeAndFlush(msg + "\r\n"); } }finally { group.shutdownGracefully(); } } public static void main(String[] args) throws Exception { new GroupChatClient("127.0.0.1", 7000).run(); } }

import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; public class GroupChatClientHandler extends SimpleChannelInboundHandler<String> { //从服务器拿到的数据 @Override protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception { System.out.println(msg.trim()); } }