JPA 使用 Criteria 查找日期在开始日期和结束日期之间可以为空的实体答案

【问题标题】：JPA find entities where date is between start and end date that can be null using CriteriaJPA 使用 Criteria 查找日期在开始日期和结束日期之间可以为空的实体
【发布时间】：2013-03-25 07:57:46
【问题描述】：

CriteriaBuilder builder = em.getCriteriaBuilder();
    CriteriaQuery cQuery = builder.createQuery();
    Root<AcsTemplateDateJPA> root = cQuery.from(AcsTemplateDateJPA.class);
    ParameterExpression<Date> d = builder.parameter(Date.class);
    cQuery.where(builder.between(d, root.<Date>get("inservicedate"), root.<Date>get("outservicedate"))); 
    Query query = em.createQuery(cQuery.select(root.get("acstemplateid"))).setParameter(d, planDate, TemporalType.DATE);
    List results =query.getResultList();

here outService date 可以为null（结束无限在未来）如何添加这个条件？

谢谢，

【问题讨论】：

标签： jpa criteria-api

【解决方案1】：

我会将日期比较分成两个块，并测试 outservicedate isNull()。比如：

Predicate startPredicate = builder.greaterThanOrEqualTo(root.<Date>get("inservicedate"), d);
Path<Date> outServiceDate = root.<Date>get("outservicedate");
Predicate endPredicate = builder.or(builder.isNull(outServiceDate), builder.lessThanOrEqualTo(outServiceDate, d));
Predicate finalCondition = builder.and(startPredicate, endPredicate);

【讨论】：

【解决方案2】：

这应该是不言自明的：

                @Override
                public Predicate toPredicate( Root<OrganizationCommission> root, CriteriaQuery<?> query,
                                              CriteriaBuilder cb )
                {
                    // The predicate validFrom - the column should contains null or values less than validityDate
                    Predicate validFrom = cb.or( root.get( OrganizationCommission_.validFrom ).isNull(),
                                                 cb.lessThanOrEqualTo(
                                                         root.get( OrganizationCommission_.validFrom ),
                                                         validityDate ) );
                    // The predicate validTo - the column should contains null or values greater than validityDate
                    Predicate validTo = cb.or( root.get( OrganizationCommission_.validTo ).isNull(),
                                               cb.greaterThanOrEqualTo( root.get( OrganizationCommission_.validTo ),
                                                                        validityDate ) );
                    Predicate predicate = cb.conjunction();
                    predicate.getExpressions().add( cb.and( validFrom, validTo ) );
                    return predicate;
                }

【讨论】：