在休眠中以对象格式读取特定列

Question

我必须阅读 hibernate 中的一些特定列。我写过这样的方法

Branch getBranch(long branchId)
{
    String query = "select distinct bran.branch.branchId,bran.branch.branchName from Location bran where bran.branch.branchId =:branchId";
    Session session = getSession();
    session.beginTransaction();
    Query buildQuery =  getSession().createQuery(query).setParameter("branchId", branchId);
    List<Object[]> countryList = buildQuery.list();
    Branch branch = null;
    for(Object[] obj : countryList)
    {
        branch  = new Branch((Long)obj[0] , (String)obj[1]);
    }
    session.close();
    return branch;
}

但在这里我必须手动构造我不想要的对象。我想以对象形式阅读结果，我不想手动构建对象。我的实体是这样的

public final class Location  implements Comparable<Location>{

    @Id
    @Column(name = Tables.LOCATION.LOCATION_ID, nullable = false, precision = 15, scale = 0, updatable = false, insertable = false)
    private long locationId;

    @Column(name = Tables.LOCATION.LOCATION_NAME, length = 60, updatable = false, insertable = false)
    private String locationName;

    @Embedded
    private Country country;

    @Embedded
    private Branch branch;

分支不映射到实体，但它是可嵌入的。我想以 DTO 的形式读取数据，所以我已经完成了 ResultTransformer 类，但它只适用于 sqlQuery 而不是 HQL（如果我错了，请纠正我）。我无法更改我的查询。请帮助我

Answer 1

Hibernate 可以通过在 HQL 中使用 new 关键字 (called dynamic instantiation/constructor expression) 为您做到这一点：

只需将您的查询更改为：

select new your.package.name.Branch(bran.branch.branchId,bran.branch.branchName) from Location bran where bran.branch.branchId =:branchId