void handleSaveVisitInfo(VisitInfo visitInfo) {
   String sql =
       "INSERT INTO visit_info(name,visit_quantity,type) "
           + " VALUES ('"
           + visitInfo.getName()
           + "','"
           + visitInfo.getVisitQuantity()
           + "','"
           + visitInfo.getType()
           + "');";
   this.getJt().execute(sql);
 }
 public void saveVisitByYear() {
   SqlRowSet s =
       this.queryForRowSet(
           "SELECT year,COUNT(*) AS visit " + " FROM log_visit " + " GROUP BY year ;");
   while (s.next()) {
     VisitInfo visitInfo = new VisitInfo();
     visitInfo.setName(s.getString("year"));
     visitInfo.setVisitQuantity(s.getInt("visit"));
     visitInfo.setType("year");
     handleSaveVisitInfo(visitInfo);
   }
 }