Question

已经编写了一个搜索服务，其中基于搜索输入数据形成查询。这里我使用分页，每次只获取提到的开始和最大值。

由于客户需要获得总记录数，因此使用以下代码

inPaginationDto.setTotalRecords(q.getResultList().size());

每次都会获取所有记录，影响很大。

有没有办法在JPQL中使用相同的查询方法更好地获取计数。

public class IncidentReportingRepoCustomImpl implements IncidentReportingRepoCustom{


    private static final MohLogger logger = MohLogFactory.getLoggerInstance(IncidentReportingRepoCustomImpl.class.getName());

    @PersistenceContext
    private EntityManager em;

    @Override
    public PaginationDto fetchIncidents(IncidentHdrSearchDto incidentHdrSearchDto) throws BusinessException {

        PaginationDto inPaginationDto = new PaginationDto();
        List<IncidentHdr> incidentHdrs = null;
        StringBuilder query = null;
        try{
            query = new StringBuilder();
            query.append(ReposJPQL.GET_INCIDENT_DETAILS);

            Map<String, Object> parameters = new HashMap<String, Object>();
            List<String> criteria = new ArrayList<String>();

            createIncidentSearchQuery(parameters,criteria, incidentHdrSearchDto);

            //append the query criteria          
            if (criteria.size() > 0) {
                for (int i = 0; i < criteria.size(); i++) {
                    query.append(" AND ");
                    query.append(criteria.get(i));
                }
            }   

            Query q = em.createQuery(query.toString());
            //logger.info("@@@@@@@@@@@@@@ QUERY @@@@@@@@@@@@@@ "+ query.toString());

            //set parameters
            for (Entry<String, Object> entry : parameters.entrySet()) {
                q.setParameter(entry.getKey(), entry.getValue());
            }

                inPaginationDto.setTotalRecords(q.getResultList().size());

            //pagination
            if(inPaginationDto.getTotalRecords() > incidentHdrSearchDto.getMaxResult() && incidentHdrSearchDto.getFirstResult() != null && incidentHdrSearchDto.getMaxResult() != null){
                q.setFirstResult(incidentHdrSearchDto.getFirstResult());        
                q.setMaxResults(incidentHdrSearchDto.getMaxResult());
            }

            incidentHdrs = q.getResultList();
        }catch(IllegalArgumentException | IllegalStateException | DataAccessException | EntityNotFoundException e){
            logger.error(e.getMessage());
            throw new BusinessException(e);
        }
        inPaginationDto.setPaginatedList(incidentHdrs);
        return inPaginationDto;
    }

/**
 * To generate query for incident search
 * @param parameters
 * @param criteria
 * @param incidentHdrDto
 */


private void createIncidentSearchQuery(Map<String, Object> parameters, List<String> criteria, IncidentHdrSearchDto incidentHdrSearchDto) {
        if(incidentHdrSearchDto.getIncidentSrNo() != null) {
            criteria.add("upper(inc.incidentSrNo) like :incidentSrNo");
            parameters.put("incidentSrNo" ,"%"+ incidentHdrSearchDto.getIncidentSrNo().toUpperCase()+"%");
        }

        if(incidentHdrSearchDto.getCategoryMast() != null) {
            criteria.add("inc.categoryMast.catCode = :catCode");
            parameters.put("catCode", incidentHdrSearchDto.getCategoryMast().getCatCode());
        }   


        if(incidentHdrSearchDto.getLocationMast() != null) {
            criteria.add("inc.locationMast.locCode = :location");
            parameters.put("location", incidentHdrSearchDto.getLocationMast().getLocCode());
        }

        if(incidentHdrSearchDto.getPatientId() != null) {
            criteria.add("inc.patientId = :patientId");
            parameters.put("patientId", incidentHdrSearchDto.getPatientId());
        }

        if(incidentHdrSearchDto.getAmsWorkOrderNo() != null) {
            criteria.add("inc.amsWorkOrderNo = :amsWorkOrderNo");
            parameters.put("amsWorkOrderNo", incidentHdrSearchDto.getAmsWorkOrderNo());
        }

        if(incidentHdrSearchDto.getTypeMast() != null){
            criteria.add("cm.typeCode = :typeCode");
            parameters.put("typeCode", incidentHdrSearchDto.getTypeMast().getTypeCode());
        }

        if(incidentHdrSearchDto.getSentinelYn() != null){
            if(incidentHdrSearchDto.getSentinelYn()){
                criteria.add("inc.sentinelYn = :sentinelYn");
                parameters.put("sentinelYn", "Y");
            }else{
                criteria.add("inc.sentinelYn = :sentinelYn");
                parameters.put("sentinelYn", "N");
            }
        }


        //get incidents which are reported with in 'x' hours.
        if(incidentHdrSearchDto.getReportedWithIn() != null){
            criteria.add(" (24 *(inc.createdTime - inc.incidentTime )) <= :withInHours");
            parameters.put("withInHours", incidentHdrSearchDto.getReportedWithIn());
        }



        //severity based search, data need to fetch from the view.
        if(incidentHdrSearchDto.getSeverityCode() != null){
            criteria.add("inc.categoryMast.catCode IN ("+ReposJPQL.GET_CAT_SEVERITY+")"
                    + " OR inc.subCategoryMast.subCatCode IN ("+ReposJPQL.GET_SUB_CAT_SEVERITY+")");
            parameters.put("severityCode", incidentHdrSearchDto.getSeverityCode());
        }
    }
}

这是初始选择查询

public String GET_INCIDENT_DETAILS = "SELECT inc FROM IncidentHdr inc LEFT JOIN inc.categoryMast cm LEFT JOIN inc.subCategoryMast sub LEFT OUTER JOIN inc.incidentDtls  WHERE 1 = 1" ;

Answer 1

将您的选择更改为：

Criteria API

long count(final Class<T> type){
    CriteriaBuilder qb=getEntityManager().getCriteriaBuilder();
    CriteriaQuery<Long> cq=qb.createQuery(Long.class);
    cq.select(qb.count(cq.from(type)));
    return getEntityManager().createQuery(cq).getSingleResult();
}

JPQL

public String GET_INCIDENT_DETAILS = "SELECT count(inc) FROM IncidentHdr inc LEFT JOIN inc.categoryMast cm LEFT JOIN inc.subCategoryMast sub LEFT OUTER JOIN inc.incidentDtls  WHERE 1 = 1" ;

按SELECT count(inc) FROM，结果是记录数。您可以重复使用查询，但删除getFirstResult和getMaxResult()并将q.getResultList()更改为q.getSingleResult()

在服务器端分页中获取总记录数而不会影响性能

1 个答案: