public DatagramPacket[] makePackets(byte[] data, InetAddress IP, int portNumber)    {
   // create packet buffer
   ByteBuffer buffer = ByteBuffer.allocate(packetSize);

   // calculate number of packets
   int dataSize = packetSize - 10;
   int totalPackets = data.length / dataSize;
   if(data.length % dataSize > 0)
       totalPackets++;

   System.out.println("Total Packets " + totalPackets);

   DatagramPacket[] pkts = new DatagramPacket[totalPackets];

   for(int seqNumber = 0; seqNumber < totalPackets; seqNumber++)
   {
       // insert metadata
       buffer.putChar(informUpdate);
       buffer.putInt(seqNumber);
       buffer.putInt(totalPackets);

       // adds data to the buffer
       if(seqNumber == totalPackets -1) // if last packet adjust length to avoid null pointer
           buffer.put(data, seqNumber * dataSize, data.length - seqNumber*dataSize);
       else
           buffer.put(data, seqNumber * dataSize, dataSize);

       // create packet
       byte[] sendData = buffer.array();
       // add packets to packet array and clear buffer
       pkts[seqNumber] = new DatagramPacket(sendData, sendData.length, IP, portNumber);
       System.out.println(new String(pkts[seqNumber].getData())); // <- Check if packets are being made correctly
       buffer.clear();
   }
   // this shows prints all elements in pkts which proves all data is the same
   for(int i = 0; i < pkts.length; i++)
       System.out.println(new String(pkts[i].getData()));
   return pkts;    }


希望我以可读格式添加了代码。提前谢谢!

最佳答案

执行此操作时:

byte[] sendData = buffer.array();


您在每次循环迭代中都检索相同的字节数组。您创建的每个DatagramPacket都在重复使用相同的字节数组。

最简单的解决方案是克隆字节数组,因为Java中的每个数组都有一个公共的clone()方法,该方法不会引发任何异常:

byte[] sendData = buffer.array().clone();

10-08 05:43
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