Java watchservice，如何找到創建文件的目錄？

Question

我正在嘗試使用Java Watchservice（NIO）來監視多個目錄，我可以在所有目錄中看到create事件，但是無法追溯到創建文件的目錄。

例如，每當創建一個新文件時，我只能看到一個文件名（沒有路徑），如何知道創建事件是在Faxfolder還是Faxfolder2上觸發的

System.out.println("START MONITORING  **************");


Path faxFolder = Paths.get("E:\\activiti\\monitor\\m1");
Path faxFolder2 = Paths.get("E:\\activiti\\monitor\\m2");
WatchService watchService = FileSystems.getDefault().newWatchService();
faxFolder.register(watchService, StandardWatchEventKinds.ENTRY_CREATE);
faxFolder2.register(watchService, StandardWatchEventKinds.ENTRY_CREATE);


boolean valid = true;
WatchKey watchKey = watchService.take();
for (WatchEvent<?> event : watchKey.pollEvents()) {
    WatchEvent.Kind kind = event.kind();
    if (StandardWatchEventKinds.ENTRY_CREATE.equals(event.kind())) {
        String fileName = event.context().toString();
        System.out.println(fileName);

    }
}

Answer 1

注冊watchService時，將為該目錄提供WatchKey 。 您應該記住哪個鍵與哪個目錄一起使用。

System.out.println("START MONITORING  **************");


Path faxFolder = Paths.get("E:\\activiti\\monitor\\m1");
Path faxFolder2 = Paths.get("E:\\activiti\\monitor\\m2");
WatchService watchService = FileSystems.getDefault().newWatchService();
Map<WatchKey,Path> keyMap = new HashMap<>();
WatchKey watchKey1 = faxFolder.register(watchService, StandardWatchEventKinds.ENTRY_CREATE);
keyMap.put(watchKey1, faxFolder);
WatchKey watchKey2 = faxFolder2.register(watchService, StandardWatchEventKinds.ENTRY_CREATE);
keyMap.put(watchKey2, faxFolder2);


while (!Thread.currentThread().isInterrupted()) {
    WatchKey watchKey = watchService.take();
    Path dir = keyMap.get(watchKey);
    for (WatchEvent<?> event : watchKey.pollEvents()) {
        WatchEvent.Kind kind = event.kind();
        if (StandardWatchEventKinds.ENTRY_CREATE.equals(event.kind())) {
            Path relativePath = (Path) event.context();
            String fileName = dir.resolve(relativePath).toString();
            System.out.println(fileName);

        }
    }
}

您的監視循環應等待事件（ WatchService.take() ），然后解決事件（ watchKey.pollEvents() ）。 所有這些都將適用於相同的WatchKey 。 然后，取下一個密鑰，該密鑰可能用於另一個目錄。

Answer 2

Path newFile = ev.context();
Path absolutePath = newFile.toAbsolutePath();