如何在 Java 中接收多个 UDP 数据报数据包

Question

我创建了一个小演示，其功能是：
- 在UDPClient中：
+ 用户输入两句话：句子A和句子B
+ 而不是将它们传递给 UDPServer

- 在UDP服务器中：
+ 这两句话将是 大写
+ 将这两个大写的句子传回 UDPClient

问题是，当我将两个句子从UDPClient传递给UDPServer时，例如
："aa"和"bb"。因此，在UDPServer中，我可以准确地获得"aa"和"bb"。但是当我从UDPServer返回大写的句子："AA"和"BB"到UDPClient时，我只能得到"AA"。处理后，如何在UDPClient中准确获得"AA"和"BB"？
这是我的代码：
UDP 客户端：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
public class UDPClient extends Thread {
static int port = 1234;
public UDPClient() {
}
@Override
public void run() {
    super.run();
    while (true) {
        try {
            DatagramSocket clientSocket = new DatagramSocket(5678);
            BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
            InetAddress IPAddress = InetAddress.getByName("localhost");
            byte[] sendData = new byte[1024];
            byte[] sendData1 = new byte[1024];
            byte[] receiveData = new byte[1024];
            System.out.println("nInput sentenceA : " );
            String sentence = inFromUser.readLine();
            System.out.println("Input sentenceB : " );
            String sentence1 = inFromUser.readLine();
            sendData = sentence.getBytes();
            sendData1 = sentence1.getBytes();
            DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 1234);
            clientSocket.send(sendPacket);
            DatagramPacket sendPacket1 = new DatagramPacket(sendData1, sendData1.length, IPAddress, 1234);
            clientSocket.send(sendPacket1);
            DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
            clientSocket.receive(receivePacket);
            String modifiedSentenceA = new String(receivePacket.getData());
            String modifiedSentenceB = new String(receivePacket.getData());
            System.out.println("FROM SERVER : " + " sentenceA : " + modifiedSentenceA + ", sentenceB : " + modifiedSentenceB);
            clientSocket.close();
        } catch (SocketException ex) {
            System.out.println(ex);;
        } catch (UnknownHostException ex) {
            System.out.println(ex);;
        } catch (IOException ex) {
            System.out.println(ex);
        }
    }
}
public static void main(String[] args) throws SocketException {
    Thread t = new UDPClient();
    t.start();
}
}

UDPServer ：

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

public class UDPServer extends Thread{

public UDPServer(){
}
@Override
public void run() {
    super.run(); //To change body of generated methods, choose Tools | Templates.
        try {
        DatagramSocket serverSocket = new DatagramSocket(1234);
        byte[] receiveData = new byte[1024];
        byte[] sendData = new byte[1024];
        byte[] sendData1 = new byte[1024];
        while(true){
            DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
            serverSocket.receive(receivePacket);
            String sentence = new String(receivePacket.getData());
            String sentence1 = new String(receivePacket.getData());
            System.out.println("RECEIVED " + sentence + " sentence1 : " + sentence1);
            InetAddress IPAddress = receivePacket.getAddress();
            int port = receivePacket.getPort();
            String capitalizedSentence = sentence.toUpperCase();
            String b = sentence1.toUpperCase();
            sendData = capitalizedSentence.getBytes();
            sendData1 = b.getBytes();
            DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
            serverSocket.send(sendPacket);
            DatagramPacket sendPacket1 = new DatagramPacket(sendData1, sendData1.length, IPAddress, port);
            serverSocket.send(sendPacket1);

        }
    } catch (SocketException ex) {
        System.out.println(ex);;
    } catch (IOException ex) {
        System.out.println(ex);;
    }
}
public static void main(String[] args){
    Thread serverThead = new UDPServer();
    serverThead.start();
}
}

Answer 1

DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
clientSocket.receive(receivePacket);
String modifiedSentenceA = new String(receivePacket.getData());
String modifiedSentenceB = new String(receivePacket.getData());

您的客户端只执行一个接收。您正在打印两次收到的数据包，但它是相同的数据包。