Question

我有一个在循环中接收UDP数据包的Java应用程序：

while (running) {
    try {
        // Block until a packet is received on the port
        byte[] buffer = new byte[1024];
        DatagramPacket receivePacket = new DatagramPacket(buffer, buffer.length);
        serverSocket.receive(receivePacket);
        ByteArrayInputStream byteIn = new ByteArrayInputStream(receivePacket.getData(), 0, receivePacket.getLength());
        DataInputStream dataIn = new DataInputStream(byteIn);

        // Print packet
        String packetString = "";
        while((packetString = dataIn.readLine()) != null) {
            Log.d("WiFi", packetString);
        }

    } catch (IOException ex) {
        Log.d("WiFi", "Problem receiving: " + ex.toString());
    }
}

当我收到数据包时，其中许多数据包按预期到达，但每隔一段时间，我就得到一个分为两部分的数据包：

103, -5.84, 5.64, 140.72, #A-=-22.53,-50.18,248.83,  #G-=52.00,-69.00,-18.00,   #M-=-146.66,-155.18,151.06,   2575012
103, -6.51, 5.62, 140.41, #A-=-22.53,-51.20,248.83,  #G-=23.00,44.00,-7.00,   #M-=-146.21,-156.13,151.06,   2575036
103, -7.23, 5.65, 140.09, #A-=-19.46,-49.15,243.71,  #G-=17.00,68.00,-2.00,   #M-=-144.85,-155.18,151.06,   2575063
103, -7.76, 5.60, 139.81, #A-=-17.41,-50.18,240.64,  #G-=17.00,71.00,0.00,   #M-=-143.94,-155.65,153
.47,   2575090
103, -8.51, 5.34, 139.40, #A-=-12.29,-47.10,233.47,  #G-=31.00,-1.00,-5.00,   #M-=-144.85,-154.70,151.87,   2575135
103, -9.20, 4.76, 138.95, #A-=-15.36,-50.18,239.62,  #G-=22.00,30.00,-3.00,   #M-=-146.66,-156.13,151.87,   2575200
103, -9.82, 4.46, 138.61, #A-=-15.36,-47.10,239.62,  #G-=33.00,1.00,-3.00,   #M-=-145.76,-156.13,152.27,   2575266
103, -10.38, 4.07, 138.23, #A-=-14.34,-48.13,235.52,  #G-=30.00,4.00,-7.00,   #M-=-144.85,-155.65,152.27,   2575372
103, -10.90, 3.76, 137.90, #A-=-14.34,-48.13,237.57,  #G-=29.00,19.00,-4.00,   #M-=-145.30,-156.13,151.47,   2575520
103, -11.41, 3.53, 137.44, #A-=-15.36,-48.13,235.52,  #G-=25.00,18.00,-4.00,   #M-=-146.21,-155.18,151.47,   2576917

正如您在第4行和第5行所看到的，最后的4个尾随字符已被切断，剩余字符的新数据包已到达。从我对UDP的阅读中，每个人都警告说UDP并不能保证数据包的到达。在我的情况下，这不是一个问题;丢失的数据包听到或者不会破坏我的应用程序。但是，我没有发现任何关于数据包不一定到达的完整信息。事实上，我已经读过这个不会发生。

通常如何处理？我很难知道到达的数据包是否完整，我可以等待下一个数据包并附加数据。

Answer 1

你描述的是不可能的。 UDP数据报完好无损地完成或完全到达。服务器必须以两个数据报发送数据。

如何处理到达碎片的UDP数据包

1 个答案: