Sql sql = Sqls.create("SELECT MONTH, SUM(money)  FROM ptbalance $condition");
	sql.setCondition(Cnd.where("balancerid","=",ptid).and("state","=",1).groupBy("month").orderBy("month", "asc"));
	sql.setCallback(Sqls.callback.map());
	final Map map = new HashMap<>();
	sql.setCallback(new SqlCallback() {
        public Object invoke(Connection conn, ResultSet rs, Sql sql) throws SQLException {
            List<Map<String, Double>> list = new LinkedList<Map<String, Double>>();
            while (rs.next())
            	map.put(rs.getString("month"), rs.getDouble("SUM(money)"));
            return map;
        }
    });
	dao.execute(sql);
	Map lm=sql.getObject(Map.class);

dao.execute(sql);这个报错空指针，开始都是好好的，貌似是service继承IdNameEntityService后，就开始报错，这个错在哪儿啊？