How to find files that match a wildcard string in Java?

Question

This should be really simple. If I have a String like this:

../Test?/sample*.txt

then what is a generally-accepted way to get a list of fil

Answer 1

Here are examples of listing files by pattern powered by Java 7 nio globbing and Java 8 lambdas:

    try (DirectoryStream<Path> dirStream = Files.newDirectoryStream(
            Paths.get(".."), "Test?/sample*.txt")) {
        dirStream.forEach(path -> System.out.println(path));
    }

or

    PathMatcher pathMatcher = FileSystems.getDefault()
        .getPathMatcher("regex:Test./sample\\w+\\.txt");
    try (DirectoryStream<Path> dirStream = Files.newDirectoryStream(
            new File("..").toPath(), pathMatcher::matches)) {
        dirStream.forEach(path -> System.out.println(path));
    }

Answer 2

Since Java 8 you can use Files#find method directly from java.nio.file.

public static Stream<Path> find(Path start,
                                int maxDepth,
                                BiPredicate<Path, BasicFileAttributes> matcher,
                                FileVisitOption... options)

Example usage

Files.find(startingPath,
           Integer.MAX_VALUE,
           (path, basicFileAttributes) -> path.toFile().getName().matches(".*.pom")
);

Answer 3

Implement the JDK FileVisitor interface. Here is an example http://wilddiary.com/list-files-matching-a-naming-pattern-java/

Answer 4

Try FileUtils from Apache commons-io (listFiles and iterateFiles methods):

File dir = new File(".");
FileFilter fileFilter = new WildcardFileFilter("sample*.java");
File[] files = dir.listFiles(fileFilter);
for (int i = 0; i < files.length; i++) {
   System.out.println(files[i]);
}

To solve your issue with the TestX folders, I would first iterate through the list of folders:

File[] dirs = new File(".").listFiles(new WildcardFileFilter("Test*.java");
for (int i=0; i<dirs.length; i++) {
   File dir = dirs[i];
   if (dir.isDirectory()) {
       File[] files = dir.listFiles(new WildcardFileFilter("sample*.java"));
   }
}

Quite a 'brute force' solution but should work fine. If this doesn't fit your needs, you can always use the RegexFileFilter.