Monitor subfolders with a Java watch service

Question

I am using watchKey to listen for a file change in a particular folder.

Path _directotyToWatch = Paths.get(\"E:/Raja\");
WatchService watcherSvc         


        

Answer 1

The reason why you're not getting the file name created/modified inside a subfolder is given by Stephen C in his answer.

Here is a simple example of how to register directories and subdirectories to watch them for the events you are interested in:

/**
 * Register the given directory and all its sub-directories with the WatchService.
 */
private void registerAll(final Path start) throws IOException {
    // register directory and sub-directories
    Files.walkFileTree(start, new SimpleFileVisitor() {

        @Override
        public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
                throws IOException {
            dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
            return FileVisitResult.CONTINUE;
        }

    });

}

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Check out the official Java Tutorials: Watching a Directory for Changes. There you can find very nice explanations and examples with the source code.

Particularly you'll be interested in this example of how to watch a directory (or directory tree) for changes to files: WatchDir.java.

The method I supplied above was taken from this example (omitting some parts for brevity).
Read the tutorial for the details.