Traverse a directory tree with a FileVisitor and print every file that matches a Glob pattern.

FileFinder.java

import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;

/**
 * Traverse a directory and print every file that matches a Glob pattern. In this example, the users home dir is
 * searched for .java and .py files.
 */
public class FileFinder extends SimpleFileVisitor<Path> {

    private final PathMatcher matcher;
    private int numMatches = 0;

    public FileFinder(String globPattern) {
        this.matcher = FileSystems.getDefault().getPathMatcher("glob:" + globPattern);
    }

    public int getNumMatches() {
        return this.numMatches;
    }

    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attr) {
        Path name = file.getFileName();
        if (name != null && this.matcher.matches(name)) {
            this.numMatches++;
            System.out.printf("Found: %s%n", file);
        }
        return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attr) {
        Path name = dir.getFileName();
        if (name != null && name.toString().startsWith(".")) {
            System.out.printf("Skipping hidden dir: %s%n", name);
            return FileVisitResult.SKIP_SUBTREE;
        }
        return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult visitFileFailed(Path file, IOException ioe) {
        System.out.printf("Could not visit file '%s': %s%n", ioe.getMessage(), file);
        return FileVisitResult.CONTINUE;
    }

    public static void main(String[] args) throws IOException {

        Path startingDir = Paths.get(System.getProperty("user.home"));
        FileFinder finder = new FileFinder("*.{java,py}");
        Files.walkFileTree(startingDir, finder);

        System.out.printf("Finder found %d files!", finder.getNumMatches());
    }
}