public long getLastJoinTime(String uid, String activityId) {
   long lastTime = 0;
   Connection conn = null;
   PreparedStatement ps = null;
   ResultSet rs = null;
   try {
     conn = DBUtil.getConnection();
     String sql =
         "select * from `ssyh_main`.`activity_join` where `uid` = ? and `activity_id`=? order by `create_time` desc;";
     ps = conn.prepareStatement(sql);
     ps.setString(1, uid);
     ps.setString(2, activityId);
     rs = ps.executeQuery();
     if (rs.next()) {
       lastTime = StringUtil.timestamp2long(rs.getTimestamp("create_time"));
     }
   } catch (SQLException e) {
     e.printStackTrace();
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     DBUtil.close(rs, ps, conn);
   }
   return lastTime;
 }