Java:每隔几秒创建一次文件

Question

我正在使用 ScheduledThreadPoolExecutor 每 fileIntervalInSeconds 秒创建一个文件:

executorService = new ScheduledThreadPoolExecutor(1);
        executorService.scheduleAtFixedRate(new Runnable()
        {
            @Override
            public void run()
            {
                    File file = new File(fileName);
                    if (file.exists())
                    {
                        Log.debug("creating new file");
                        openFileWriter(file);
                    }

            }
        }, fileIntervalInSeconds, fileIntervalInSeconds, TimeUnit.SECONDS);
    }
private void openFileWriter() throws FileSystemNotificationException
{

        // 1 - close exist writer
        writer.close();
        // 2 - rename to backup file name
          ...
        // 3 - create new file      
        FileWriter writerFile = new FileWriter(fileName, true);
        writer = new PrintWriter(writerFile);

}

而且我一直在向文件写入警报消息:

private synchronized void writeLine(String line) throws InterruptedException
{
    writer.println(line);
}

我的问题是:

1. 我如何确保在 writer 未关闭时我正在使用它？ (writer.close())
2. 如何在开始写入之前等待 ScheduledThreadPoolExecutor 完成创建文件

Answer 1

在写入文件之前如何检查文件是否存在。无需后台线程或同步

private synchronized void writeLine(String line) {
    if (!file.exists())
       reopenWritingFile();
    writer.println(line);
}