@Path("/")
public class Step2Action extends Action {
    ...
    public ActionResult step2() {
        foodFiles = getFiles("/images/food");
        animalFiles = getFiles("/images/animal");
        landscapeFiles = getFiles("/images/landscape");
        foodSize = FileUtil.sizeOfFiles(foodFiles);
        animalSize = FileUtil.sizeOfFiles(animalFiles);
        landscapeSize = FileUtil.sizeOfFiles(landscapeFiles);
        return new Forward("step2.jsp");
    }

    private File[] getFiles(String path) {                ┓
        File[] files = new File(context.getRealPath(path))｜
                           .listFiles();                  ｜
        return files;                                     ｜
    }                                                     ┛①
}

public class FileUtil {
    public static long sizeOfFiles(File[] files) {
        long totalSize = 0;
        for (File file : files) {
            totalSize += file.length();
        }
        return totalSize;
    }
}