通过任务队列实现推送消息功能

痛定思痛。 2022-09-04 11:42 197阅读 0赞

*  在服务器端每次初始化通道时，把新通道添加到一个集合中；
 *  在处理器中，获取当前所有客户端对应的通道，根据通道获取通道所属的事件循环，往事件循环的任务队列提交发送消息的任务；
 *  循环事件的任务会被执行，通过任务将消息发送到对应通道；

服务端：

package com.tech.netty.netty;
    
    
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.ChannelOption;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.channel.socket.nio.NioServerSocketChannel;
    
    import java.util.ArrayList;
    import java.util.HashSet;
    import java.util.List;
    import java.util.Set;
    
    /**
     * @author lw
     * @since 2021/8/11
     **/
    public class NettyServer {
    
        public static final Set<SocketChannel> customerChannelList=new HashSet<>();
    
        public static void main(String[] args) throws InterruptedException {
    
            //1 创建两个线程组bossGroup workerGroup
            //2 bossGroup处理客户端连接请求 workerGroup处理客户端数据读写请求
            //3 他们都是事件循环组 默认含有CPU核数*2个事件循环NioEventLoop
            NioEventLoopGroup bossGroup = new NioEventLoopGroup(1);
            NioEventLoopGroup workerGroup = new NioEventLoopGroup(2);
            try {
                //创建服务器端启动对象，进行参数配置
                ServerBootstrap serverBootstrap = new ServerBootstrap();
    
                serverBootstrap.group(bossGroup, workerGroup)  //设置两个线程组
                        .channel(NioServerSocketChannel.class)  //设置服务器端通道为NioServerSocketChannel
                        .option(ChannelOption.SO_BACKLOG, 128) //设置连接队列允许的连接个数
                        .childOption(ChannelOption.SO_KEEPALIVE, true) //设置连接连接状态为活动连接
                        .childHandler(new ChannelInitializer<SocketChannel>() { //给workerGroup NioEventLoop通过管道添加处理器
                            @Override
                            protected void initChannel(SocketChannel socketChannel) throws Exception {
                                socketChannel.pipeline().addLast(new NettyServerHandler());
                                customerChannelList.add(socketChannel);
                                customerChannelList.forEach(c->{
                                    System.out.println("|"+c.hashCode()+"|");
                                });
                            }
                        });
                System.out.println("...服务器 is ready...");
                //启动服务器并绑定一个端口
                ChannelFuture channelFuture = serverBootstrap.bind(6668).sync();
                //对通道的关闭事件进行监听
                channelFuture.channel().closeFuture().sync();
            } finally {
                bossGroup.shutdownGracefully();
                workerGroup.shutdownGracefully();
            }
        }
    }

每次有新的客户端连接时，通道初始化方法会被执行，通道会被加入到Set中

package com.tech.netty.netty;
    
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.util.CharsetUtil;
    import lombok.extern.slf4j.Slf4j;
    
    import java.util.Set;
    import java.util.concurrent.TimeUnit;
    
    /**
     * @author lw
     * @since 2021/8/11
     **/
    //自定义一个Handler
    @Slf4j
    public class NettyServerHandler extends ChannelInboundHandlerAdapter {
    
        //读取客户端发送的消息
        // ChannelHandlerContext 是一个上下文对象，可以获取通道和管道信息
        // msg 是客户端发送的消息
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
    //        System.out.println("服务器读取线程 "+Thread.currentThread().getName());
    //        System.out.println("server ctx:"+ctx);
    //        Channel channel = ctx.channel();
    //        ChannelPipeline pipeline = ctx.pipeline();
    //        ByteBuf byteBuf = (ByteBuf) msg;
    //        System.out.println("客户端发送消息是："+byteBuf.toString(CharsetUtil.UTF_8));
    //        System.out.println("客户端地址："+channel.remoteAddress());
    //        ctx.channel().eventLoop().execute(new Runnable() {
    //            @Override
    //            public void run() {
    //                try {
    //                    Thread.sleep(5*1000);
    //                } catch (InterruptedException e) {
    //                    e.printStackTrace();
    //                }
    //                ctx.writeAndFlush(Unpooled.copiedBuffer("hello 客户端 1",CharsetUtil.UTF_8));
    //                log.info("channel:"+ctx.channel().hashCode());
    //            }
    //        });
    //
    //        ctx.channel().eventLoop().execute(new Runnable() {
    //            @Override
    //            public void run() {
    //                try {
    //                    Thread.sleep(5*1000);
    //                } catch (InterruptedException e) {
    //                    e.printStackTrace();
    //                }
    //                ctx.writeAndFlush(Unpooled.copiedBuffer("hello 客户端 2",CharsetUtil.UTF_8));
    //                log.info("channel:"+ctx.channel().hashCode());
    //            }
    //        });
    //
    //        ctx.channel().eventLoop().schedule(new Runnable() {
    //            @Override
    //            public void run() {
    //                try {
    //                    Thread.sleep(5*1000);
    //                } catch (InterruptedException e) {
    //                    e.printStackTrace();
    //                }
    //                ctx.writeAndFlush(Unpooled.copiedBuffer("hello 客户端 3",CharsetUtil.UTF_8));
    //                log.info("channel:"+ctx.channel().hashCode());
    //            }
    //        },15, TimeUnit.SECONDS);
            Set<SocketChannel> channels = NettyServer.customerChannelList;
            channels.forEach(channel -> {
                channel.eventLoop().execute(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            Thread.sleep(5 * 1000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        channel.writeAndFlush(Unpooled.copiedBuffer("hellow word",CharsetUtil.UTF_8));
                        log.info("eventloop hashcode::{},channel hashcode::"+channel.hashCode(),channel.eventLoop().hashCode());
                    }
                });
            });
    
            log.info("go on...");
        }
    
        //数据读取完毕
        @Override
        public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
            //发送数据
            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) throws Exception {
            ctx.close();
        }
    }

当处理器读取数据时，会往Set中的所有通道对应的事件循环的任务队列中提交任务
    任务的内容是：往当前通道发送消息
    在任务队列的任务被执行时候完成消息发送

客户端

package com.tech.netty.netty;
    
    import io.netty.bootstrap.Bootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.channel.socket.nio.NioSocketChannel;
    
    /**
     * @author lw
     * @since 2021/8/11
     **/
    public class NettyClient {
        public static void main(String[] args) throws InterruptedException {
            //客户端需要一个事件循环组
            NioEventLoopGroup eventExecutors = new NioEventLoopGroup();
            try {
                // 创建客户端启动对象 并配置参数
    
                Bootstrap bootstrap = new Bootstrap();
                bootstrap.group(eventExecutors)  //设置线程组
                        .channel(NioSocketChannel.class)  //设置客户端通道
                        .handler(new ChannelInitializer<SocketChannel>() {  //设置处理器
                            @Override
                            protected void initChannel(SocketChannel socketChannel) throws Exception {
                                socketChannel.pipeline().addLast(new NettyClientHandler());
                            }
                        });
                System.out.println("...客户端 is ready...");
                //连接服务器
                ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 6668).sync();
                //对通道关闭事件进行监听
                channelFuture.channel().closeFuture().sync();
            } finally {
                eventExecutors.shutdownGracefully();
            }
    
        }
    }

package com.tech.netty.netty;
    
    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;
    
    /**
     * @author lw
     * @since 2021/8/11
     **/
    public class NettyClientHandler extends ChannelInboundHandlerAdapter {
    
        //当通道就绪会触发该方法 给服务器发送数据
        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
            System.out.println("client ctx:"+ctx);
            ctx.writeAndFlush(Unpooled.copiedBuffer("hello 服务器", CharsetUtil.UTF_8));
        }
    
        //当通道有读取事件时触发
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            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) throws Exception {
            ctx.close();
        }
    }