Listing all files that matches the regular expression recursively

Question

I need to load all files that matches the path or regular expression.

If the path is

"C:\Users\me\Desktop\project\src\test\resources\screenshots/*/*.png"

it should find all screenshots in "screenshots" folder. If the path is

C:\Users\me\Desktop\project\src\test\resources\screenshots/first.png

it should find only the one file.

I was trying to list all files that match the criteria using:

File dir = new File("/");
FileFilter fileFilter = new WildcardFileFilter(absolutePath);
File[] files = dir.listFiles(fileFilter);

but this is not recursive and finds files only in home folder.

I tried to also use Spring way:

ClassLoader cl = this.getClass().getClassLoader();
ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(cl);
return resolver.getResources(pattern);

But this expects only relative paths and looking for files in classpath.

What is the correct, standard and pretty way how to do this?

@SimonMartinelli no, there is nothing about regexps in there.. — Johnyb, Aug 16 '21 at 14:21
Sure it is! Files.walk gives you a stream of files and then you can filter howerver you like Files.walk(Paths.get(path)).filter() — Simon Martinelli, Aug 16 '21 at 14:24
@SimonMartinelli Files.walk however ends when there is an exception, like AccessDenied. Isnt it also super non efficent? It seems it just literally traverse everything — Johnyb, Aug 16 '21 at 14:31
https://stackoverflow.com/questions/66542005/files-walkfiletree-vs-files-walk-performance-on-windows-ntfs — Simon Martinelli, Aug 16 '21 at 14:34
@SimonMartinelli there is still problem with access denied exception if it meets some folder it has no access to — Johnyb, Aug 16 '21 at 15:45

score -1 · Answer 1 · answered Aug 16 '21 at 15:21

-1

Files.walk(Paths.get(path))
   .filter(Files::isRegularFile)
   .filter(p ->p.toString().matches(".*\\.png$"))
   .forEach(System.out::println);

Passing your screenshots folder path as a String ('path') to the above will filter for you

answered Aug 16 '21 at 15:21

g00se

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this still throws AccessDenied exception if there is some folder it does not have access to on the way. + the regexp can be present anywhere in the path,.. – Johnyb Aug 16 '21 at 15:45
Not sure if that's filterable. Shall check – though it begs the question: "Why, in your own screenshots tree, would there be files to which you don't have access?" – g00se Aug 16 '21 at 15:55
that tree was just an example, the path can be literally anything user wants it to be – Johnyb Aug 17 '21 at 09:19
You need to go for the 'long version' of recursing the fs to be able to cope with errors probably – g00se Aug 17 '21 at 15:11

Listing all files that matches the regular expression recursively

1 Answers1