public class Topic {
    private int tpid;
    private String tptitle;
    private User user;
    private String tpcontent;
    private Date tptime;
    private Board board;
    private int tpreplynum;
    private String tpstop;
    private String tpico;
        .......

                        s = HibernateUtil.getSession();
            String hql = "from Topic as topic where topic.board.bdid=:n ";// from Object
            Query query = s.createQuery(hql);
            query.setInteger("n", tpboardid);
            topiclist = query.list();// executQuery();
                        ActionContext ac = ActionContext.getContext();
                        ac.put("topiclist", topiclist);