Files.list和Files.walkFileTree和Files.walk有什么区别,maxdepth = 1？

Question

如果我想要做一些文件只对目录的第一级,是有使用之间的差异Files.list(...)或Files.walkFileTree(...)或Files.walk(...)？

Files.walkFileTree(directory, Collections.emptySet(), 1, new SimpleFileVisitor<Path>() {
    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
        doSomething(file);
        return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult visitFileFailed(Path file, IOException exc) {
        // log exc
        return FileVisitResult.CONTINUE;
    }
});

与

Files.list(directory)
    .forEach(path -> {
        try {
            doSomething(path);
        } catch (IOException exc) {
            // log exc
        }
    });

与

Files.walk(directory, 1)
    .forEach(path -> {
        try {
            doSomething(path);
        } catch (IOException exc) {
            // log exc
        }
});

Answer 1

使用以下代码作为测试,我得到了问题的悬而未决.之间的主要区别walk*和list是list(dir)给人流目录中的文件 dir,而这两个walk*方法走路子树的说法,包括树,目录本身的根源.

walk和之间的区别在于walkFileTree它们为树的行走提供了不同的接口:walkFileTreetake FileVisitor,walkgive Stream<Path>.

public class FilesTest {
    public static void main(String[] args) {
        final String pwd = System.getProperty("user.dir");
        System.out.println("Working Directory = " + pwd);
        Path dir = Paths.get(pwd);
        System.out.println("Files.walk");
        try {
            Files.walk(dir, 1).forEach(path -> FilesTest.doSomething("walk", path));
        } catch (IOException e) {
            logException("walk", e);
        }
        System.out.println("Files.walkFileTree");
        try {
            Files.walkFileTree(dir, Collections.emptySet(), 1, new SimpleFileVisitor<Path>() {
                @Override
                public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                    doSomething("visitFile", file);
                    return FileVisitResult.CONTINUE;
                }

                @Override
                public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {
                    logException("visitFile", exc);
                    return FileVisitResult.CONTINUE;
                }
            });
        } catch (IOException e) {
            logException("walkFileTree", e);
        }
        System.out.println("Files.list");
        try {
            Files.list(dir).forEach(path -> FilesTest.doSomething("dir", path));
        } catch (IOException e) {
            logException("dir", e);
        }
    }

    private static void logException(String title, IOException e) {
        System.err.println(title + "\terror: " + e);
    }

    private static void doSomething(String title, Path file) {
        System.out.println(title + "\t: " + file);
    }
}