JPA implement paging

JPA implement paging

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Jpa themselves have a basic query methods to achieve paging, as long as they find a front-end plug-in page on the Internet, then use Jpa queries to the data to it.

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Page biography of the current page and each page size to the background, the background like this deal:

public List<PsrAnalysisTask> findAnalysisTask(String loginName,
            Long analysisTempId,Integer pageIndex, Integer pageSize) {
        Query query = null;
            query = em.createQuery("select a from PsrAnalysisTask a where  a.createdBy=:createdBy and a.analysistempId =:analysistempId ");
            query.setParameter("createdBy", loginName);
            query.setParameter("analysistempId", analysisTempId);
            query.setFirstResult((pageIndex-1)*pageSize);
            query.setMaxResults(pageSize);
        List<PsrAnalysisTask> as = query.getResultList();
        return as;

    }

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Of course, the value of the page to be returned, in addition to the list of queries as well as the total number of queries to:

@Override
public Integer getTotalCount(String loginName) {
    return Integer.valueOf(em.createQuery(
            "SELECT COUNT(*) FROM PsrAnalysisTask e WHERE e.createdBy = :createdBy")
.setParameter("createdBy",loginName).getSingleResult().toString());
}

At this point it is fully able to meet the needs of a page, filling it