gphm/PHM-admin/phm-netty/src/main/java/com/phm/netty/client/NettyUdpClient.java

package com.phm.netty.client;

import java.net.InetSocketAddress;

import org.springframework.stereotype.Component;

import com.phm.common.exception.GlobalException;
import com.phm.netty.client.handler.NettyUdpClientHandler;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
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.DatagramPacket;
import io.netty.channel.socket.nio.NioDatagramChannel;
import io.netty.util.Attribute;
import io.netty.util.AttributeKey;
import lombok.extern.slf4j.Slf4j;

/**
 * @Description NettyUdpClient
 * @Author WGK
 * @Date 2023/10/30 15:25
 */
@Slf4j
@Component
public class NettyUdpClient {
    public void bind(String address, int port, byte[] data, String customValue) {
        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
        try {
            Bootstrap clientBootstrap = new Bootstrap();
            clientBootstrap = clientBootstrap.group(eventLoopGroup).channel(NioDatagramChannel.class)
                .option(ChannelOption.SO_BROADCAST, true).handler(new ChannelInitializer<NioDatagramChannel>() {
                    @Override
                    protected void initChannel(NioDatagramChannel ch) {
                        // 使用 AttributeKey 定义一个键
                        final AttributeKey<String> key = AttributeKey.valueOf("customKey");

                        // 获取 Channel 的 Attribute
                        Attribute<String> attr = ch.attr(key);

                        // 设置自定义值
                        attr.set(customValue);

                        // 在这里添加你的处理器
                        ch.pipeline().addLast(new NettyUdpClientHandler());
                    }
                });
            Channel channel = clientBootstrap.bind(8989).sync().channel();
            // 给服务端发送请求信息
            channel.writeAndFlush(new DatagramPacket(Unpooled.copiedBuffer(data), new InetSocketAddress(address, port)))
                .sync();
            // 方式一：查询等待超时 单位s， 超时自动关闭
            // channel.closeFuture().await(10000);
            // 方式er：原地等候返回消息，再关闭连接
            channel.closeFuture().sync();
        } catch (Exception e) {
            log.error(e.getMessage());
            throw new GlobalException("在线下载数据异常，请重新下载");
        } finally {
            log.info("netty client udp close!");
            eventLoopGroup.shutdownGracefully();
        }
    }

    // 测试
    public static void main(String[] args) {

        // 向网段内的所有机器广播UDP消息，这个没试过是不是这个原理
        // new BootNettyUdpClient().bind("255.255.255.255",9999,"I am client");

        // 指定某个套接字地址和发送的内容可以发送消息
        // 该方式也可以封装成一个udp的客户端的send类
        // new NettyUdpClient().bind("127.0.0.1", 9999, "I am client");

    }
}