Files.walk से Directory Trees पर चलना

import java.nio.file.*;
import java.util.stream.*;

try (Stream<Path> stream = Files.walk(Path.of("/home/user/projects"))) {
    stream.forEach(System.out::println);
} // stream and underlying resources closed automatically

Path root = Path.of("/home/user/projects");

// Only immediate children (depth 1)
try (var stream = Files.walk(root, 1)) {
    stream.filter(p -> !p.equals(root)) // exclude start path
          .forEach(System.out::println);
}

Path root = Path.of(".");

try (var stream = Files.walk(root)) {
    long fileCount = stream
        .filter(Files::isRegularFile)
        .count();
    System.out.println("Files: " + fileCount);
}

try (var stream = Files.walk(Path.of("/src"))) {
    List<Path> javaFiles = stream
        .filter(Files::isRegularFile)
        .filter(p -> p.toString().endsWith(".java"))
        .collect(Collectors.toList());
    javaFiles.forEach(System.out::println);
}

try (var stream = Files.walk(Path.of("/home/user/data"))) {
    long totalBytes = stream
        .filter(Files::isRegularFile)
        .mapToLong(p -> {
            try { return Files.size(p); }
            catch (IOException e) { return 0; }
        })
        .sum();
    System.out.printf("Total: %.2f MB%n", totalBytes / 1_048_576.0);
}

// Only immediate children:
try (var stream = Files.list(Path.of("/home/user"))) {
    stream.forEach(System.out::println);
}

import java.nio.file.attribute.BasicFileAttributes;

try (var stream = Files.find(
        Path.of("/home/user"),
        Integer.MAX_VALUE,
        (p, attrs) -> attrs.isRegularFile() && attrs.size() > 1_000_000
)) {
    stream.forEach(p -> System.out.println("Large file: " + p));
}

Path toDelete = Path.of("/tmp/workdir");
try (var stream = Files.walk(toDelete)) {
    stream.sorted(Comparator.reverseOrder())
          .forEach(p -> {
              try { Files.delete(p); }
              catch (IOException e) { e.printStackTrace(); }
          });
}

Path src = Path.of("/source"), dst = Path.of("/destination");
try (var stream = Files.walk(src)) {
    stream.forEach(p -> {
        try {
            Path target = dst.resolve(src.relativize(p));
            if (Files.isDirectory(p)) Files.createDirectories(target);
            else Files.copy(p, target, StandardCopyOption.REPLACE_EXISTING);
        } catch (IOException e) { throw new RuntimeException(e); }
    });
}

try (var stream = Files.walk(Path.of("/"),
        FileVisitOption.FOLLOW_LINKS)) { // caution: symlink loops
    // ...
} catch (IOException e) {
    System.err.println("Access error: " + e.getMessage());
}

Files.walkFileTree(Path.of("/home/user"), new SimpleFileVisitor<Path>() {
    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
        System.out.println("File: " + file);
        return FileVisitResult.CONTINUE;
    }
    @Override
    public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) {
        System.out.println("Dir: " + dir);
        return FileVisitResult.CONTINUE;
    }
});