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我创建了一个运行后台服务的 android 应用程序，该服务执行以下操作：

1) 要求 UDP 服务器向其发送 100 个数据包

2) 在 while(true) 循环中接收数据包

3) 使用 setSoTimeout 使接收在 5 分钟后超时并退出循环

上述操作每 2 分钟重复一次。当手机连接到 PC 并使用 adb logcat 监控每一步时，该应用程序运行良好，但当手机与 PC 断开连接时，该应用程序停止工作。然后在文件中记录每个步骤表明最后一步是接收步骤，之后套接字不会超时。可能的原因是什么？有没有其他方法可以让我以恒定的时间间隔完成预期的任务？这是从服务启动的线程的运行函数：

   public void downlink() 
{
    String path = extStorageDirectory + "/" + appFolder + "/REP_DT_" + Long.toString(System.currentTimeMillis()) + ".txt";
    File file = new File(path);
    if(!file.exists())
    try 
    {
        file.createNewFile();
    }
    catch (IOException e) 
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    String p = extStorageDirectory + "/Goonj/logtput.txt";
    try {
        DatagramSocket clientSocket = new DatagramSocket();
        try {
            FileWriter fw = new FileWriter(path,true);
            fw.write("\n\n");
            fw.close();             
            clientSocket.setSoTimeout(120000);
            InetAddress IPAddress = InetAddress.getByName(IP);
            long id = System.currentTimeMillis();      
            byte[] sendData = createMessage(id,0,1400,150);     
            DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 9010);
            clientSocket.send(sendPacket);      
            byte[] receiveData = new byte[10240];
            boolean flag = true;
            while(flag)//for(int i=0; i<100; i++)
            {      
                DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length); 
                writeToLog(p,"START");
                clientSocket.receive(receivePacket);
                writeToLog(p,"END");
                long time = System.currentTimeMillis();
                String data = new String(receivePacket.getData(), 0, receivePacket.getLength());
                System.out.println(data);
                fw = new FileWriter(path,true);
                fw.write(Long.toString(getSeqno(data)) + " " + Long.toString(time) + "\n");
                fw.close();
            }                               
        }
        catch(SocketTimeoutException e)
        {
            writeToLog(p,"SOCKET EXCEPTION HAS BEEN CAUGHT!!!" + Long.toString(System.currentTimeMillis()));
            e.printStackTrace();
        }
        catch(IOException e)
        {
            writeToLog(p,"IO EXCEPTION HAS BEEN CAUGHT!!!" + Long.toString(System.currentTimeMillis()));
            e.printStackTrace();
        }
        clientSocket.close();
    }
    catch(SocketException e){}
    //fw.close();
}
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