如何在Java中接收多个UDP数据报数据包？

Question

我创建了一个小的演示，其具有的功能是：
- 在UDPClient：
+用户输入的两句话：sentenceA和sentenceB
+比它们传递到UDPServer

- 在UDPServer：
+那些两句话将 资本
+通过这两个句子资本回UDPClient

的问题是，当我通过两句话从UDPClient到UDPServer
例如：“AA”和“BB”。所以，在UDPServer中，我可以准确地获得“aa”和“bb”。但是当我返回大写的句子：从UDPServer到UDPClient的“AA”和“BB”时，我只能得到“AA”。在处理后，我如何在UDPClient中准确地同时获得“AA”和“BB”？
这里是我的代码：
UDP客户：

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。您正在打印接收到的数据包两次，但它是同一个数据包。