向 DatagramSocket 添加超时-receive() [英] Adding timeout to DatagramSocket - receive()

问题描述

我需要在这部分代码上创建一个 10 秒的超时时间

I need to create a 10 second timeout on this part of the code

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

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.

I need it to listed for incoming packets for 10s if it receives a packet before 10s it would skip down to if statement in case it reaches 10s it would jump down to else and resend the packet. Is this possible and how could i do this iam pretty new to this.

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) {

    }

}

推荐答案

这应该适用于您的示例.

That should work for your example.

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...
}

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