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DirectoryStream.Filter example for listing files based on a specific date / time

I am trying to research an example DirecoryStream.Filterfor newDirectoryStreamwhere I can find a list of all the files in a directory (and all its subdirectories) that are older than 60 days, as an example.

DirectoryStream<Path> dirS = Files.newDirectoryStream(Paths.get("C:/myRootDirectory"), <DirectoryStream.filter>);

for (Path entry: dirS)
    {
        System.out.println(entry.toString());
    }

Should the above code have a DirectoryStream.filter directory? This will be a big help as I participate in a project where I try to delete files older than a certain timestamp and pre-java 1.7 File.listFiles () just freezes.

Can the walkFileTree () function provide a parameter?

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2 answers

If I get it right, you have two situations:

  • Create a custom filterone to select files older than 60 days.
  • ( FileTree)

60 Calendar:

DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
    @Override
    public boolean accept(Path entry) throws IOException {BasicFileAttributes attr = Files.readAttributes(entry,BasicFileAttributes.class);
    FileTime creationTime = attr.creationTime();
    Calendar cal = Calendar.getInstance();
    int days = cal.fieldDifference(new Date(creationTime.toMillis()),Calendar.DAY_OF_YEAR);
        return (Math.abs(days) > 60);
        }
  };

. , walkFileTree() .

FileVisitor, , , 7 - SimpleFileVisitor.

, , - preVisitDirectory SimpleFileVisitor :

Files.walkFileTree(dirs, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult preVisitDirectory(Path file,
                    BasicFileAttributes attrs) {

preVisitDirectory return FileVisitResult.CONTINUE;, - , preVisitDirectory 1 .

Files.walkFileTree(dirs, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult preVisitDirectory(Path file,
                    BasicFileAttributes attrs) {

                DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
                    @Override
                    public boolean accept(Path entry) throws IOException {
                        BasicFileAttributes attr = Files.readAttributes(entry,
                                BasicFileAttributes.class);
                        FileTime creationTime = attr.creationTime();
                        Calendar cal = Calendar.getInstance();
                        int days = cal.fieldDifference(
                                new Date(creationTime.toMillis()),
                                Calendar.DAY_OF_YEAR);
                        return (Math.abs(days) > 60);
                    }
                };
                try (DirectoryStream<Path> stream = Files.newDirectoryStream(
                        file, filter)) {
                    for (Path path : stream) {
                        System.out.println(path.toString());
                    }
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
                return FileVisitResult.CONTINUE;

            }
        });

, :

public static void main(String[] args) throws IOException {
        Path dirs = Paths.get("C:/");

        Files.walkFileTree(dirs, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult preVisitDirectory(Path file,
                    BasicFileAttributes attrs) {

                DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
                    @Override
                    public boolean accept(Path entry) throws IOException {
                        BasicFileAttributes attr = Files.readAttributes(entry,
                                BasicFileAttributes.class);
                        FileTime creationTime = attr.creationTime();
                        Calendar cal = Calendar.getInstance();
                        int days = cal.fieldDifference(
                                new Date(creationTime.toMillis()),
                                Calendar.DAY_OF_YEAR);
                        return (Math.abs(days) > 60);
                    }
                };
                try (DirectoryStream<Path> stream = Files.newDirectoryStream(
                        file, filter)) {
                    for (Path path : stream) {
                        System.out.println(path.toString());
                    }
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
                return FileVisitResult.CONTINUE;

            }
        });

    }
+6

DirectoryStream.Filter, true, Path 60 .

DirectoryStream<Path> dirStream = Files.newDirectoryStream(Paths.get("/some/path"), new Filter<Path>() {
    @Override
    public boolean accept(Path entry) throws IOException {
        FileTime fileTime = Files.getLastModifiedTime(entry);
        long millis = fileTime.to(TimeUnit.MILLISECONDS);
        Calendar today = Calendar.getInstance();
        // L is necessary for the result to correctly be calculated as a long 
        return today.getTimeInMillis() > millis + (60L * 24 * 60 * 60 * 1000);
    }
});

, Path, .. Path newDirectoryStream(..).

, Files.walkFileTree(..), , . FileVisitor, List Set Path, , , Filter.

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