How to read all files in a folder from Java?

Answer 1

Given a baseDir, lists out all the files and directories below it, written iteratively.

    public static List listLocalFilesAndDirsAllLevels(File baseDir) {

    List  collectedFilesAndDirs   = new ArrayList<>();
    Deque remainingDirs           = new ArrayDeque<>();

    if(baseDir.exists()) {
        remainingDirs.add(baseDir);

        while(!remainingDirs.isEmpty()) {
            File dir = remainingDirs.removeLast();
            List filesInDir = Arrays.asList(dir.listFiles());
            for(File fileOrDir : filesInDir)  {
                collectedFilesAndDirs.add(fileOrDir);
                if(fileOrDir.isDirectory()) {
                    remainingDirs.add(fileOrDir);
                }
            }
        }
    }

    return collectedFilesAndDirs;
}