Java 打印目录下所有文件包含指定关键字的行

在一个目录及其子所有子目录下搜索所有文件，打印包含指定关键字的行

代码实现：

public class BlockingQueueTest {

    private static final int FILE_QUEUE_SIZE = 10;
    private static final int SEARCH_THREADS = 100;
    private static final Path DUMMY = Path.of("");
    private static BlockingQueue<Path> queue = new ArrayBlockingQueue<>(FILE_QUEUE_SIZE);

    // 12.5.1 阻塞队列
    public static void main(String[] args) {

        try (var in = new Scanner(System.in)) {
            System.out.print("Enter base directory (e.g. C:\\Files\\test):");
            String directory = in.nextLine();

            System.out.print("Enter keyword (e.g. volatile)");
            String keyword = in.nextLine();

            Runnable enumerator = () -> {
                try {
                    enumerate(Path.of(directory));
                    queue.put(DUMMY);

                } catch (IOException e) {
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            };

            new Thread(enumerator).start();

            for (int i = 1; i < SEARCH_THREADS; i++) {
                Runnable searcher = () -> {
                    try {
                        var done = false;
                        while (!done) {
                            Path file = queue.take();
                            if (file == DUMMY) {
                                queue.put(file);
                                done = true;
                            } else {
                                search(file, keyword);
                            }
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                };
                new Thread(searcher).start();
            }
        }
    }

    /**
     * Recursively enumerates all files in a given directory and its subdirectories.
     *
     * @param directory the directory in which to start.
     * @return void
     */
    public static void enumerate(Path directory) throws IOException, InterruptedException {

        try (Stream<Path> children = Files.list(directory)) {
            for (Path child : children.collect(Collectors.toList())) {
                if (Files.isDirectory(child))
                    enumerate(child);
                else
                    queue.put(child);

            }
        }
    }

    /**
     * Search a file for a given keyword and prints all matching lines.
     *
     * @param file    the file to search
     * @param keyword the key word to search for
     * @return void
     */
    public static void search(Path file, String keyword) throws IOException {

        try (var in = new Scanner(file, StandardCharsets.UTF_8)) {
            int lineNumber = 0;

            while (in.hasNextLine()) {
                lineNumber++;
                String line = in.nextLine();
                if (line.contains(keyword))
                    System.out.printf("%s:%d:%s%n", file, lineNumber, line);
            }
        }
    }
}