code: public byte[] getFileBytes(String filename) throws CmsImportExportException {
  
          try {
              // is this a zip-file?
              if (getZipFile() != null) {
  
                  ZipEntry entry = getZipEntry(filename);
                  InputStream stream = getZipFile().getInputStream(entry);
                  int size = new Long(entry.getSize()).intValue();
                  return CmsFileUtil.readFully(stream, size);
              } else {
                  // no - use directory
                  File file = getFile(filename);
                  return CmsFileUtil.readFile(file);
              }
          } catch (FileNotFoundException fnfe) {
              CmsMessageContainer msg = Messages.get().container(Messages.ERR_IMPORTEXPORT_FILE_NOT_FOUND_1, filename);
              if (LOG.isErrorEnabled()) {
                  LOG.error(msg.key(), fnfe);
              }
              throw new CmsImportExportException(msg, fnfe);
          } catch (IOException ioe) {
              CmsMessageContainer msg = Messages.get().container(
                  Messages.ERR_IMPORTEXPORT_ERROR_READING_FILE_1,
                  filename);
              if (LOG.isErrorEnabled()) {
                  LOG.error(msg.key(), ioe);
              }
              throw new CmsImportExportException(msg, ioe);
          }
      }
docs: Returns a byte array containing the content of the file.<p>
  
  @param filename the name of the file to read, relative to the folder or zip file
  
  @return a byte array containing the content of the file
  
  @throws CmsImportExportException if something goes wrong