java - 向 DatagramSocket 添加超时-receive()

Question

我需要在这部分代码上创建 10 秒超时

DatagramPacket getack = new DatagramPacket(incoming, incoming.length);
socket.receive(getack);

我需要它列出 10 秒的传入数据包，如果它在 10 秒之前收到一个数据包，它将跳到 if 语句，以防它达到 10 秒，它会跳到 else 并重新发送数据包。这可能吗？我怎么能这样做？我对此很陌生。

private static void sendDATA() {
    outgoing = new byte[512]; // Empty array
    try {
        ByteBuffer sDATA = ByteBuffer.allocate(516);
        // 512 - 2 byte opcode, 2 byte block #, 512 data

        DatagramPacket data = new DatagramPacket(outgoing, outgoing.length, InetAddress.getByName(clientip), clientport);
        InputStream fis = new FileInputStream(new File(FILE));

        int a;
        int block = 1; 

        while((a = fis.read(outgoing,0,512)) != -1)
        {
            data.setLength(a);
            sDATA.put((byte)3);
            sDATA.put((byte)block);
            sDATA.put(outgoing);
            socket.send(data); 

            while(true) {
                DatagramPacket getack = new DatagramPacket(incoming, incoming.length);
                socket.receive(getack);

                if(incoming[0] == 3 && incoming[1] == block) {
                    break;
                } else {
                    socket.send(data);
                }
            }

        }       
    } catch (Exception e) {

    }

}

Answer 1

这应该适用于您的示例。

socket.setSoTimeout(10000);
while(true) {
    DatagramPacket getack = new DatagramPacket(incoming, incoming.length);
    try {
        socket.receive(getack);
    } catch (SocketTimeoutException e) {
       // resend
       socket.send(data);
       continue;
    }
    // check received data...
}

Answer 2

socket.setSoTimeout(10000);
socket.receive(getack);
socket.setSoTimeout(0);