Question

I am making a search module that will be able to filter data according to some criteria.

I already made the following:

public class SearchModuleBean implements Serializable{

    @PersistenceContext
    EntityManager entityManager;

    private Date departureDate;
    private Date returnDate;

    public List<Flight> search(){
        CriteriaBuilder cb = entityManager.getCriteriaBuilder();
        CriteriaQuery<Flight> criteriaQuery = cb.createQuery(Flight.class);
        Root<Flight> c = criteriaQuery.from(Flight.class);
        criteriaQuery.select(c).where(getPredicates(cb, c).toArray(new Predicate[0]));
        TypedQuery<Flight> query = entityManager.createQuery(criteriaQuery);
        System.out.println(query.getResultList());
        return query.getResultList();
    }

    private List<Predicate> getPredicates(CriteriaBuilder cb, Root<Flight> c) {
        List<Predicate> predicates = new ArrayList<>();
        predicates.add(cb.equal(c.get(Flight_.departureDate), departureDate));
        return predicates;
    }
}

Getters/Setters/Annotations and imports are not displayed here.

I have a JSF page which fills in the departure- and arrivalDates. In the getPredicates method I then check for the departureDate if it is equal to Dates in our database. The issue is that they have a different format so he never finds anything.

Answer 1

我不倾向于使用Criteria API，并且可能有另一种方法，但是您可以按以下方式使用between运算符：

private List<Predicate> getPredicates(CriteriaBuilder cb, Root<Flight> c, 
           Date departureDate) {

    List<Predicate> predicates = new ArrayList<>();

    //remove time portion from specified date: now dd/mm/yy 00:00
    Date startDate = DateUtils.truncate(departureDate, Calendar.DATE);

    //new date with time initialized to 23:59:59
    Date endDate = DateUtils.addSeconds(DateUtils.addDays(startDate, 1), - 1);

    predicates.add(cb.between(c.get(Flight_.departureDate), startDate, endDate));

    return predicates;
}

DateUtils是Commons Lang中的一类：

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.8.1</version>
</dependency>

Criteria API: Correct Date Format

1 个答案: