问如何关闭AsynchronousFileChannel

EN

    Path path = Paths.get("hello_world.txt");
    path.toFile().createNewFile();

    AsynchronousFileChannel channel = AsynchronousFileChannel.open(path, StandardOpenOption.WRITE);
    channel.write(ByteBuffer.wrap("hello".getBytes()), 0, channel, new CompletionHandler<Integer, Closeable>() {
        @Override
        public void completed(Integer result, Closeable closeMe) {
            System.out.println("Written: " + result);
            try {
                closeMe.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void failed(Throwable exc, Closeable closeMe) {
            System.err.println("Error occurred: " + exc);
            try {
                closeMe.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    });

    //wait for async task to complete
    Thread.sleep(5000L);

AsynchronousFileChannel channel = open(...);

final CompletableFuture<Void> future = new CompletableFuture();

channel.(read|write)(buffer, position, whatever, new CompletionHandler<Whatever>() {
        @Override
        public void completed(Integer result, Whatever attachment) {
            // Do whatever you need to do...
            // When completed, do
            future.complete(null);
        }
        @Override
        public void failed(Throwable exc, Whatever attachment) {
            future.completeExceptionally(exc);
        }
);

future.get(); // done; either with a result or an exception

channel.close();