Question

我有以下实体类：

@Entity
@Table(name = "auditrecord", uniqueConstraints = { @UniqueConstraint(columnNames = {
    "accountid", "repositoryid" }) })
public class AuditRecordEntity {
  private UUID accountId;
  private UUID repositoryId;
  private Date accessTime;

  @Column(name = "accountid", nullable = false, updatable = false)
  public UUID getAccountId() {
    return accountId;
  }

  @Column(name = "repositoryid", nullable = false, updatable = false)
  public UUID getRepositoryId() {
    return repositoryId;
  }

  @Temporal(TemporalType.TIMESTAMP)
  @Column(name = "accesstime", nullable = false, updatable = true)
  public Date getAccessTime() {
    return accessTime;
  }

  // setters for above fields
}

请注意accountId + repositoryId上的唯一约束，一个帐户只能有一个特定仓库的审计记录，因此同一个仓库可能有多个审计记录，每个审计记录都有不同的值。

我希望获得每个特定仓库的最新/最新的访问时间 AuditRecordEntitys列表，最好使用条件API。

需要插入下面的空格：

CriteriaBuilder criteriaBuilder = getEntityManager().getCriteriaBuilder();
CriteriaQuery<Object> criteriaQuery = criteriaBuilder.createQuery();

Root<AuditRecordEntity> root = criteriaQuery.from(AuditRecordEntity.class);
criteriaQuery.select(root);

// here


List<Predicate> predicates = new ArrayList<Predicate>();
// add predicates here.
entitySearchCriteria.addPredicates(predicates);

addEntityCriteria(criteriaBuilder, criteriaQuery, root, entitySearchCriteria, null, null);
return getPagedByQuery(criteriaQuery, pageSize, pageNumber);

Answer 1

试试这个。

DetachedCriteria maxDateQuery = DetachedCriteria.forClass(AuditRecordEntity.class);
ProjectionList proj = Projections.projectionList();
proj.add(Projections.max("accessTime"));
proj.add(Projections.groupProperty("repositoryId"));
maxDateQuery.setProjection(proj);

我不确定这是否有用，这应该会让你知道如何做到这一点。

CriteriaBuilder criteriaBuilder = getEntityManager().getCriteriaBuilder();
CriteriaQuery<Object> criteriaQuery = criteriaBuilder.createQuery();
Root<AuditRecordEntity> root = criteriaQuery.from(AuditRecordEntity.class);
Expression<Date> accessTime = root.get("accessTime");
criteriaQuery.select(criteriaBuilder.max(accessTime));
criteriaQuery.groupBy(root.get("userId"));
//other code

参考：Answer

此实体类的Criteria API / HQL

1 个答案: