code: public FileModel getChildFile(ArchiveModel archiveModel, String filePath)
      {
          filePath = FilenameUtils.separatorsToUnix(filePath);
          StringTokenizer stk = new StringTokenizer(filePath, "/");
  
          FileModel currentFileModel = archiveModel;
          while (stk.hasMoreTokens() && currentFileModel != null)
          {
              String pathElement = stk.nextToken();
  
              currentFileModel = findFileModel(currentFileModel, pathElement);
          }
          return currentFileModel;
      }
docs: Finds the file at the provided path within the archive.
  
  Eg, getChildFile(ArchiveModel, "/META-INF/MANIFEST.MF") will return a {@link FileModel} if a file named
  /META-INF/MANIFEST.MF exists within the archive
  
  @return Returns the located {@link FileModel} or null if no file with this path could be located