Question

我正在尝试在服务中实现分页。使用Cassandra作为数据库如果查询返回少量列表，我的代码工作正常。我只是过滤了数字关闭页面[硬编码为100 /不想硬编码而不是作为参数返回]和偏移值。所以对于每个请求我都不想进行查询。我确定应该有一种可能的方法来在查询本身中设置偏移值。我的代码 -

  @RequestMapping(value = "/find/customerreqbyperiod", method = RequestMethod.GET,
  produces = "application/json")
  @ResponseBody
  public List<CustomerReq> findCustomerRequest(@RequestParam(value = "productid") final String pProductId,
  @RequestParam(value = "dataperiod") final String pdataPeriod,
  @RequestParam(value = "offset") final int offset)
  {
   List<CustomerReq> requestList = null;

   try
   {
    requestList = requestService.findCustomerRequest(pProductId, pdataPeriod, offset);
      if (requestList == null || offset > requestList.size()) return new ArrayList<CustomerRequestV2>();

       int numberOfItems = 10;
       int fromIndex = offset;
       int toIndex = Math.min(offset + numberOfItems, requestList.size());

        return requestList.subList(fromIndex, toIndex);
       }
  catch (final ServiceException e)
    {
     LOG.error(ERROR_RETRIEVING_LIST + pProductId, e);
    }
   return requestList;
  }

@Repository -

   @Query("select * from customer_request where product_id = ?0 and data_period = ?1")
   List<CustomerReq> findByProductIdAnddataPeriod(String productId, String dataPeriod, int offset);

请提供您宝贵的建议。谢谢！-Saurav

Answer 1

我认为你应该在这里使用Pageable例如：

public interface ProductRepository extends JpaRepository<Product, Long> {
    @Query("select cr from customer_request cr where cr.product_id = :productId and cr.data_period = :dataPeriod")
    Page<CustomerReq> findByProductIdAnddataPeriod(@Param("productId") String productId, @Param("dataPeriod") String dataPeriod, Pageable pageable);
}

并使用offset：

传递PageRequest

PageRequest pageRequest = new PageRequest(pageNumber, offset);
Page<CustomerReq> customerReqsPage = findByProductIdAnddataPeriod("productId","datePeriod", pageRequest);
List<CustomerReq> customerReqs = customerReqsPage.getContent();

<强> UDP ：不幸的是，Cassandra不支持它。 JIRA票证：jira.spring.io/browse/DATACASS-56

Pagination Spring数据中的问题

1 个答案: