Question

我试图查看有关使用Hibnerate返回列表的信息，但找不到符合我要求的内容，因此需要一些建议。

我有以下课程

BPDataPK：

  public class BPDataPK implements Serializable {
    private String id;
    private int userProfile;
    private Date when;      
         .....
  }

BPData：

public class BPData implements Serializable {   
   private BPDataPK dataPK;
   private Date sessionStart;
    ...
}

HibernateBPDataDAO：

public class HibernateBPDataDAO extends HibernateDaoSupport implements IBPDataDAO{
    ....
public BPData[] getSessionBPData(Session session) throws Exception {
        /**I need to get a list of BPData that matches the following
        1.  BPDataPK.id== session.getID;
        2.  BPDataPK.userProfile == session.getUserProfile;
        **3.  BPData.sessionStart  == session.getSessionStart();**
        */
    }
 }

如何返回匹配两个主键和非主键的BPData列表？

Answer 1

您不应该环顾以获取某些信息。相反，您应该阅读reference documentation。

本文档有一整章专门讨论使用HQL查询语言，另一章专门用于标准查询。由于此处有一组固定的标准，因此HQL更适合于该任务：

String hql = "select b from BPData b where b.dataPK.id = :id"
             + " and b.dataPK.userProfile = :profile"
             + " and b.sessionStart = :sessionStart";
Query q = hibernateSession.createQuery(hql);
q.setString("id", session.getID());
q.setInt("profile", session.getUserProfile());
q.setTimestamp("sessionStart", session.getSessionStart()); // or setDate, depending on the type of this field
List<BPData> result = q.list();

Answer 2

如果你正在使用hibernate的JPA实现，你可以这样做

@Entity
@NamedQuery(
    name="findByMyQuery",
    queryString="SELECT bpdata FROM BPData bpdata WHERE bpdata.dataPK = :sessionId AND bpdata.userProfile = :userProfile AND bpdata.sessionStart = :sessionStart "
)
public class BPData implements Serializable {

    private BPDataPK dataPK;
    private Date sessionStart;
        ...
    }


public BPData[] getSessionBPData(Session session) throws Exception {       

    Query queryFindByMyQuery = entityManager.createNamedQuery("findByMyQuery");
    queryEmployeeByFirstName.setParameter("sessionId", session.getID());
    queryEmployeeByFirstName.setParameter("userProfile", session.getUserProfile());
    queryEmployeeByFirstName.setParameter("sessionStart", session.getSessionStart());
    return queryEmployessByFirstName.getResultList().toArray();
 }

需要Hibernate帮助

2 个答案: