code: public static FeedLoadResult export (String feedId, String outFile, DataSource dataSource, boolean fromEditor) {
          JdbcGtfsExporter exporter = new JdbcGtfsExporter(feedId, outFile, dataSource, fromEditor);
          FeedLoadResult result = exporter.exportTables();
          return result;
      }
docs: Export a feed ID from the database to a zipped GTFS file in the specified export directory.