java spring boot实现实时udp 监听

java 实现实时udp 监听

因项目需要对接高频读卡器使用udp传输数据，后台要实时监听处理
1、监听类

package com.ruoyi.controller.Listener;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.util.logging.Logger;

/**
 * udp监听
 * @author fjh
 */

/*
 * 服务器端，实现基于UDP的用户登陆
 */
@WebListener
public class UDPListener implements ServletContextListener {
    public static Logger logger = Logger.getLogger(UDPListener.class.getName());
    public static final int MAX_UDP_DATA_SIZE = 4096;
    public static final int UDP_PORT = 26667;
    public static DatagramPacket packet = null;
    public static DatagramSocket socket = null;

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        try {
            logger.info("========启动一个线程，监听UDP数据报.PORT:" + UDP_PORT + "=========");
            // 启动一个线程，监听UDP数据报
            new Thread(new UDPProcess(UDP_PORT)).start();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    class UDPProcess implements Runnable {

        public UDPProcess(final int port) throws SocketException {
            //创建服务器端DatagramSocket，指定端口
            socket = new DatagramSocket(port);
        }

        @Override
        public void run() {
            // TODO Auto-generated method stub
            logger.info("=======创建数据报，用于接收客户端发送的数据======");
            while (true) {
                byte[] buffer = new byte[MAX_UDP_DATA_SIZE];
                packet = new DatagramPacket(buffer, buffer.length);
                try {
                    logger.info("=======此方法在接收到数据报之前会一直阻塞======");
                    socket.receive(packet);
                    new Thread(new Process(packet)).start();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }
    }

    class Process implements Runnable {
        public Process(DatagramPacket packet) throws UnsupportedEncodingException {
            // TODO Auto-generated constructor stub
            logger.info("=======接收到的UDP信息======");
            byte[] buffer = packet.getData();// 接收到的UDP信息，然后解码
//            String srt1 = new String(buffer, "GBK").trim();
            //            logger.info("=======Process srt1 GBK======" + srt1);
            String srt2 = new String(buffer, "UTF-8").trim();
            logger.info("=======Process srt2 UTF-8======" + srt2);
//            String srt3 = new String(buffer, "ISO-8859-1").trim();
//            logger.info("=======Process srt3 ISO-8859-1======" + srt3);
        }

        @Override
        public void run() {
            // TODO Auto-generated method stub
            logger.info("====过程运行=====");
            try {
                logger.info("====向客户端响应数据=====");
                //1.定义客户端的地址、端口号、数据
                InetAddress address = packet.getAddress();
                int port = packet.getPort();
                byte[] data2 = "{'request':'alive','errcode':'0'}".getBytes();
                //2.创建数据报，包含响应的数据信息
                DatagramPacket packet2 = new DatagramPacket(data2, data2.length, address, port);
                //3.响应客户端
                socket.send(packet2);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
       logger.info("========UDPListener摧毁=========");
    }


}

2、配置启动项目时启动监听

/**
 * 启动程序
 * 
 * @author fjh
 */
@SpringBootApplication(exclude = { DataSourceAutoConfiguration.class })
@ServletComponentScan
public class Application
{
    public static void main(String[] args)
    {
        // System.setProperty("spring.devtools.restart.enabled", "false");
        SpringApplication.run(Application.class, args);
        System.out.println(" 启动成功ﾞ  \n" ）;
    }
}

3、发送测试demo

package com.ruoyi.controller;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class test {
    public static final String SERVER_HOSTNAME = "localhost";
    // 服务器端口
    public static final int SERVER_PORT = 26667;
    // 本地发送端口
    public static final int LOCAL_PORT = 8888;

    public static void main(String[] args) {
        try {
            // 1，创建udp服务。通过DatagramSocket对象。
            DatagramSocket socket = new DatagramSocket(LOCAL_PORT);
            // 2，确定数据，并封装成数据包。DatagramPacket(byte[] buf, int length, InetAddress
            // address, int port)
            byte[] buf = "fengyanzushuaideyipi".getBytes();
            DatagramPacket dp = new DatagramPacket(buf, buf.length, InetAddress.getByName(SERVER_HOSTNAME),
                    SERVER_PORT);
            // 3，通过socket服务，将已有的数据包发送出去。通过send方法。
            socket.send(dp);
            // 4，关闭资源。
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}