String hql = "select new Order(o.customer,o.tradeDate,o.status,o.amount) from Order o ";
        Query query = session.createQuery(hql);
        List<Order> orders = query.list();
        for (Order order : orders) {
            System.out.println("customer"+order.getCustomer());
            System.out.println("tradeDate"+order.getTradeDate());
            System.out.println("status"+order.getStatus());
            System.out.println("amount"+order.getAmount());
        }

老是报  cannot cast错误，我构造函数都写了阿。