public List<TopicObj> getTopicTable(PreparedStatement pre, boolean join) {
        List<TopicObj> items = new LinkedList<TopicObj>();
        try {
            ResultSet rs = pre.executeQuery();
            if (rs != null) {
                while (rs.next()) {
                    TopicObj item = new TopicObj();
                    item.setTopicId(rs.getInt("topic_id"));
                    item.setName(rs.getString("name"));
                    item.setFileName(rs.getString("filename"));
                    item.setPath(rs.getString("path"));
                    item.setObjId(rs.getInt("obj_id"));
                    if(join){
                        item.setObjName(rs.getString("obj_name"));
                    }
                    items.add(item);
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return items;
    }