public enum ReportStatus {
SUCCCEED, FAILED;
}
public class Work {
@ElementCollection
@Enumerated(EnumType.STRING)
List<ReportStatus> reportStatuses;
}
考慮下面的結構,我想執行一個查詢,以找到reportStatuses過濾所有的工作。它正常工作與以下HQL語法:在CriteriaQuery中@ElementCollection(或查詢過的@ElementCollection的內容)
public List<Long> queryHQL() {
final String query = "SELECT w.id FROM Work w JOIN w.reportStatuses s WHERE s in (:rs)";
final List<ReportStatus> reportStatuses = new ArrayList<ReportStatus>();
reportStatuses.add(ReportStatus.FAILED);
return this.entityManager.createQuery(query).setParameter("rs", reportStatuses).getResultList();
}
但我想使用標準的API(JPA2),並不能弄清楚如何做到這一點。這裏是我最親近的嘗試,我認爲:
public List<Long> query() {
final List<ReportStatus> reportStatuses = new ArrayList<ReportStatus>();
reportStatuses.add(ReportStatus.FAILED);
final CriteriaBuilder builder = this.entityManager.getCriteriaBuilder();
final CriteriaQuery<Long> criteriaQuery = builder.createQuery(Long.class);
final Root<Work> workModel = criteriaQuery.from(Work.class);
final ListJoin<Work, ReportStatus> status = workModel.joinList("reportStatuses");
final Predicate predicate = status.in(reportStatuses);
criteriaQuery.where(predicate);
criteriaQuery.select(workModel.<Long> get("id"));
return this.entityManager.createQuery(criteriaQuery).getResultList();
}
我也試過用Hibernate的標準API,但作爲一個JPA2我沒能找到正確的語法。
ël檢查更新的答案。 – dira 2010-12-10 12:13:24