检查 Java 中所有文件句柄何时被释放
我想监视一个目录，当文件出现时打开它，处理它，然后将其移动到另一个目录。问题是如何检查其他程序是否已完成编写。在 Java 7 中，我可以使用 FileSystem 中的 WatchService，但我只能检查文件的创建时间。我想知道什么时候所有文件句柄都被释放。
我的第一个想法是我可以获得独占锁，但事实证明，可以在另一个应用程序实际更新文件时将其踢出。
在 Java 中执行此操作的首选方法是什么？谢谢！
I want to monitor a directory, and when a file appears there open it, process it and then move it to another directory. The problem is how to check that the other program is done writing it. With Java 7, I can use a WatchService from FileSystem, but I can only check when the files are created. What I want is to know when all file handles are released.
My first thought was that I could obtain an exclusive lock, but it turned out that it was possible to kick out another application while it was actually updating the file.
What is the preferred way to do this in Java? Thanks!
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Watcher API 目前允许您查看在监视目录中创建、修改或删除文件系统对象时的事件。他们不会告诉您其他 inotify 事件（在 Linux 上）。事实上，我认为没有办法在纯Java中做到这一点。
几周前，我自己在寻找一种方法来执行此操作，我遇到了一个邮件线程，建议您编写
FileSystemapi 的自定义实现，该实现提供支持其他文件的文件监视程序系统事件。我决定不再追求它，因为我有一个替代解决方案......基于我正在观看的文件是如何生成的知识。就我而言，这些文件是由将图像文件保存到共享驱动器的仪器生成的。解决方案是监视新创建的文件的“修改”事件流。当它停止并且几秒钟（“稳定时间”）内不再有任何消息时，就可以处理文件了。
如果该解决方案被证明不可靠，则后备方案是直接使用 inotify 调用在 C / C++ 中实现监视和初始处理（拍摄文件快照）。这将使我能够直接观察文件关闭事件。
The Watcher APIs currently allow you to see events when a file system object is created, modified or deleted in a watched directory. They don't tell you about other inotify events (on Linux). In fact, I don't think there is a way to do this in pure Java.
I was looking for a way to do this myself a few weeks ago and I came across a mail thread that suggested that you could write a custom implementation of the
FileSystemapi that provided a file watcher that supported other file system events. I decided not to pursue it because I had an alternative solution ... based on knowledge of how the files I am watching are being produced.In my case, the files are produced by instruments that save image files to a shared drive. The solution is to watch the stream of "modified" events for a newly created file. When it stops and no more have been forthcoming for a couple of seconds (the "settling time"), then the file can be processed.
If this solution proves to be unreliable, the fallback is to implement the watching and initial processing (taking a snapshot of the file) in C / C++ using the inotify calls directly. This will allow me to directly observe the file close event.
基于文件的接口最简单的方法是：
The simplest way for a filebased interface is: