Java基于ServletContextListener实现UDP监听

Java基于ServletContextListener实现UDP监听

这篇文章主要介绍了java基于ServletContextListener实现UDP监听,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

使用spring boot实现项目启动时的监听，

UDPListener

import java.io.IOException;

import java.io.UnsupportedEncodingException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.SocketException;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;

import javax.servlet.annotation.WebListener;

@WebListener

public class UDPListener implements ServletContextListener {

public static final int MAX_UDP_DATA_SIZE = 4096;

public static final int UDP_PORT = 26666;

@Override

public void contextInitialized(ServletContextEvent sce) {

System.out.println("========UDPListener Initialized=========");

try {

　　　　　　　// 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 {

DatagramSocket socket = null;

public UDPProcess(final int port) throws SocketException {

socket = new DatagramSocket(port);

}

@Override

public void run() {

// TODO Auto-generated method stub

System.out.println("=======UDPProcess======");

while (true) {

byte[] buffer = new byte[MAX_UDP_DATA_SIZE];

DatagramPacket packet = new DatagramPacket(buffer, buffer.length);

try {

socket.receive(packet);

new TdznbIoKVhread(new Process(packet)).start();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

class Process implements Runnable {

public Process(DatagramPacket packet) throws UnsupportedEncodingException {

// TODO Auto-generated constructor stub

byte[] buffer = packet.getData();// 接收到的UDP信息，然后解码

String srt1 = new String(buffer,"GBK").trim();

String srt2 = new String(buffer, "UTF-8").trim();

String srt3 = new String(buffer,"ISO-8859-1").trim();

System.out.println("=======Process srt1 GBK======" + srt1);

System.out.println("=======Process srt2 UTF-8======" + srt2);

System.out.println("=======Process srt3 ISO-8859-1======" + srt3);

}

@Override

public void run() {

// TODO Auto-generated method stub

System.out.println("====Process run=====");

}

}

@Override

public void contextDestroyed(ServletContextEvent sce) {

System.out.println("========UDPListener Destroyed=========");

}

}

DemoApplication

@SpringBootApplication

@ServletComponentScan

public class DemoApplication {

public static void main(String[] args) {

SpringApplication.run(DemoApplication.class, args);

}

}

@ServletComponentScan Servlet扫描，启动时把servlet、filter、listener自动扫描注入

UDP测试客户端（也可以用测试工具发送UDP包测试）：

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

public class UDPClientTest {

public static final String SERVER_HOSTNAME = "localhost";

// 服务器端口

public static final int SERVER_PORT = 26666;

// 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 = "你好，世界".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();

}

}

}

结果：

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