Question

我有这样的实体：

public class User
{
    private Integer idUser;
    private String user;
    private String password;
    private Perfil perfil;

    Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "idUser", unique = true, nullable = false)
    public Integer getIdUser()
    {
        return this.idUser;
    }

    public void setIdUser(Integer idUser)
    {
        this.idUser = idUser;
    }

    @Column(name = "user", nullable = false)
    public String getUser()
    {
        return this.user;
    }

    public void setUser(String user)
    {
        this.user = user;
    }

    @Column(name = "password", nullable = false)
    public String getPassword()
    {
        return this.password;
    }

    public void setPassword(String password)
    {
        this.password = password;
    }

    @OneToOne
    @JoinColumn(name = "idPerfil", nullable = false)
    public Perfil getIdPerfil()
    {
        return idPerfil;
    }

    public void setIdPerfil(Perfil idPerfil)
    {
        this.idPerfil = idPerfil;
    }
}

public class Perfil
{
    private Integer idPerfil;
    private String perfil;
    private String description;

    Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "idPerfil", unique = true, nullable = false)
    public Integer getIdPerfil()
    {
        return this.idPerfil;
    }

    public void setIdPerfil(Integer idPerfil)
    {
        this.idPerfil = idPerfil;
    }

    @Column(name = "description", nullable = false)
    public String getDescription()
    {
        return this.description;
    }

    public void setDescription(String description)
    {
        this.description = description;
    }

}

我想只获得idUser，user和idPerfil;我使用：

Session session = HibernateUtil.openSession();

        try
        {
            Criteria criteria = session.createCriteria(User.class);
            ProjectionList proList = Projections.projectionList();
            proList.add(Projections.property("idUser"), "idUser");
            proList.add(Projections.property("user"), "user");
            proList.add(Projections.property("idPerfil"), "idPerfil");
            criteria.setProjection(proList);
            criteria.setFetchMode("idPerfil.idPerfil", org.hibernate.FetchMode.JOIN);
            criteria.setResultTransformer(Transformers.aliasToBean(User.class));
            List<User> list = criteria.list();
            return list;
        }
        catch (Exception e)
        {
            throw e;
        }
        finally
        {
            session.close();
        }

对于实体用户工作正常，我得到属性especify的值，但是从idPerfil我得到所有值属性，我只想要idPerfil。我该如何进行查询？

Answer 1

尝试为idPerfil添加别名：

criteria.createAlias("idPerfil", "idp");

然后在投影中引用它：

proList.add(Projections.property("idp.idPerfil"), "idPerfil");

然后移除变压器：

criteria.setResultTransformer(Transformers.aliasToBean(User.class));

并将结果更改为：

列表list = criteria.list（）;

列表中的每个元素都是Object []数组：

for(Object data : list) {
    Object[] projection = (Object[]) data;
    Integer idUser = projection[0];
    String user = projection[1];
    Integer idPerfil= projection[3];
    ...
}

hibernate条件投影获取连接表的列

1 个答案: