Question

I have a directory, C:\myDir.

under this directory, there may be folders and various files

How can I “loop” through this directory and build up a File array of all files with a .properties extension?

I want to do some processing on these files, the reason for a File[] is to keep it dynamic (so additional properties files added in the future will be included)

I’m hoping to do something like this :

public static void main (String[] vargs)
{

   // find all .properties files
   //

   //loop through property file and process
   {
      doSomething(myFile[i]);
   }

}

public void doSomething(File myfile) {}

Answer 1

Here is a complete answer without external libs:

public class FileFinder{

    public static List<File> findFiles(final File baseDir, final String regex){
        final List<File> files = new ArrayList<File>();

        scanFolder(baseDir, Pattern.compile(regex), files);
        return files;
    }

    private static void scanFolder(final File dir,
        final Pattern pattern,
        final List<File> files){

        for(final File candidate : dir.listFiles()){
            if(candidate.isDirectory()){
                scanFolder(candidate, pattern, files);
            } else if(pattern.matcher(candidate.getName()).matches()){
                files.add(candidate);
            }
        }
    }

}

Call it like this:

public static void main(String[] args){
    List<File> filesAsList = FileFinder.findFiles(
                                new File("c:\\my\\dir"), ".*\\.properties");
    File[] filesAsArray = filesAsList.toArray(new File[filesAsList.size()]);
}