// OrderRepository.java

    private void updateAggregateRoot(Aggregate<Order> orderAggregate) {
        //only update changed fields, avoid update all fields
        OrderDO newOrderDO = new OrderDO(orderAggregate.getRoot());
        // 这里获取到的是Aggregate Root的变更字段
        Set<String> changedFields = DataObjectUtils.getChangedFields(orderAggregate.getRootSnapshot(), orderAggregate.getRoot());
        // orderMapper实际需要的是持久化对象OrderDO的变更字段 
        if (orderMapper.updateByPrimaryKeySelective(newOrderDO, changedFields) != 1) { 
            throw new OptimisticLockException(String.format("Update order (%s) error, it's not found or changed by another user",
                    orderAggregate.getRoot().getId()));
        }
    }