从零学Netty（九）Netty实现UDP服务器

我就是我 2022-12-15 06:12 241阅读 0赞

# 简介 #

*  UDP 是User Datagram Protocol的简称， 中文名是用户数据报协议
 *  UDP协议与[TCP][]协议一样用于处理数据包，在[OSI][]模型中，两者都位于[传输层][Link 1]，处于IP协议的上一层
 *  UDP有不提供数据包分组、组装和不能对数据包进行排序的缺点，也就是说，当报文发送之后，是无法得知其是否安全完整到达的
 *  UDP用来支持那些需要在[计算机][Link 2]之间传输数据的网络应用

# 实例demo #

服务端实现

/**
     * udp服务端
     *
     * @author LionLi
     */
    public class UdpServer {
    
        public static void main(String[] args) throws InterruptedException {
            EventLoopGroup group = new NioEventLoopGroup();
            try {
                Bootstrap bootstrap = new Bootstrap();
                bootstrap.group(group)
                        // 主线程处理
                        .channel(NioDatagramChannel.class)
                        // 广播
                        .option(ChannelOption.SO_BROADCAST, true)
                        // 设置读缓冲区为2M
                        .option(ChannelOption.SO_RCVBUF, 2048 * 1024)
                        // 设置写缓冲区为1M
                        .option(ChannelOption.SO_SNDBUF, 1024 * 1024)
                        .handler(new ChannelInitializer<NioDatagramChannel>() {
    
                            @Override
                            protected void initChannel(NioDatagramChannel ch) {
                                ChannelPipeline pipeline = ch.pipeline();
                                pipeline.addLast(new NioEventLoopGroup(), new UdpServerHandler());
                            }
                        });
    
                ChannelFuture f = bootstrap.bind(8088).sync();
                System.out.println("服务器正在监听......");
                f.channel().closeFuture().sync();
            } finally {
                group.shutdownGracefully();
            }
    
        }
    }

服务端业务处理实现

/**
     * 服务端业务处理
     *
     * @author LionLi
     */
    public class UdpServerHandler extends SimpleChannelInboundHandler<DatagramPacket> {
    
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) {
            System.out.println("服务端接收到消息：" + packet.content().toString(StandardCharsets.UTF_8));
            // 向客户端发送消息
            ByteBuf byteBuf = Unpooled.copiedBuffer("已经接收到消息!".getBytes(StandardCharsets.UTF_8));
            ctx.writeAndFlush(new DatagramPacket(byteBuf, packet.sender()));
        }
    }

客户端实现

/**
     * udp客户端
     *
     * @author LionLi
     */
    public class UdpClient {
    
        public static void main(String[] args) {
        EventLoopGroup group = new NioEventLoopGroup();
            try {
                Bootstrap bootstrap = new Bootstrap();
                bootstrap.group(group)
                        .channel(NioDatagramChannel.class)
                        .handler(new ChannelInitializer<NioDatagramChannel>() {
                            @Override
                            protected void initChannel(NioDatagramChannel ch) {
                                ChannelPipeline pipeline = ch.pipeline();
                                pipeline.addLast(new UdpClientHandler());
                            }
                        });
                Channel channel = bootstrap.bind(8089).sync().channel();
                InetSocketAddress address = new InetSocketAddress("localhost", 8088);
                ByteBuf byteBuf = Unpooled.copiedBuffer("你好服务器".getBytes(StandardCharsets.UTF_8));
                channel.writeAndFlush(new DatagramPacket(byteBuf, address)).sync();
                channel.closeFuture().await();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                group.shutdownGracefully();
            }
        }
    
    }

客户端业务处理

/**
     * 客户端业务处理
     *
     * @author LionLi
     */
    public class UdpClientHandler extends SimpleChannelInboundHandler<DatagramPacket> {
    
        //接受服务端发送的内容
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) {
            System.out.println("客户端接收到消息：" + packet.content().toString(StandardCharsets.UTF_8));
            // 向客户端发送消息
            ByteBuf byteBuf = Unpooled.copiedBuffer("你好服务器".getBytes(StandardCharsets.UTF_8));
            ctx.writeAndFlush(new DatagramPacket(byteBuf, packet.sender()));
        }
    
    }

# 测试 #

分别启动服务端与客户端

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70 1][]

项目已上传到gitee

地址: [netty-demo][]

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[TCP]: https://baike.baidu.com/item/TCP
[OSI]: https://baike.baidu.com/item/OSI
[Link 1]: https://baike.baidu.com/item/%E4%BC%A0%E8%BE%93%E5%B1%82/4329536
[Link 2]: https://baike.baidu.com/item/%E8%AE%A1%E7%AE%97%E6%9C%BA/140338
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70]: /images/20221123/64f6f0488e6c45b8aa2c8e2cd87c7d10.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70 1]: /images/20221123/98e77d4f902b4c9f968bdd611df2ad26.png
[netty-demo]: https://gitee.com/JavaLionLi/LionLi-Labs/tree/master/netty-demo