UDP接收器代码仅接收一个数据包

Question

Th following code only receives on packet of data. I have sent different sizes of data to see if data is being received on the receiver. I only get the first packet and I do not see any other packets. What could be the cause of the missing packets. Since I am receiving 12 bytes every time. Do I need to clear the buffer or make it larger. What practices should I follow.

import java.net.DatagramSocket;
import java.net.DatagramPacket;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

public class Reciever {
  public static void main(String[] args) {
    try {
      DatagramSocket s = new DatagramSocket(2010);
      byte[] data = new byte[12];
      DatagramPacket p = new DatagramPacket(data, 12);
      s.receive(p);
      System.out.println("got packet");
      ByteBuffer bb = ByteBuffer.allocate(12).order(ByteOrder.LITTLE_ENDIAN);
      bb.put(data);
      bb.rewind();
      System.out.println(bb.getFloat());
      System.out.println(bb.getFloat());
      System.out.println(bb.getFloat());
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

Answer 1

You receive only one UDP packet because you call receive only once and then exit. If more than one packet is sent you will receive one and the others are dropped and lost forever.

Add a loop to receive more than one packet:

try {
    DatagramSocket s = new DatagramSocket(2010);
    byte[] data = new byte[12];
    DatagramPacket p = new DatagramPacket(data, 12);
    while (true) {
        s.receive(p);
        System.out.println("got packet");
        ByteBuffer bb = ByteBuffer.allocate(12).order(ByteOrder.LITTLE_ENDIAN);
        bb.put(data);
        bb.rewind();
        System.out.println(bb.getFloat());
        System.out.println(bb.getFloat());
        System.out.println(bb.getFloat());
    }
} catch (IOException e) {
  e.printStackTrace();
}

Answer 2

I got it working by adding a while loop and moving the DatagramSocket s = new DatagramSocket(2010); byte[] data = new byte[12]; outside the loop