Question

我试图了解如何从hibernate获取列表 - 但我不断收到错误，例如无法直接在组件上创建对象。虽然我已经找到了解决这个问题的方法，但是我发现了创建别名的参考资料 - 这似乎在我的情况下失败了。具体来说，我试图在复合键的一个元素上查询对象。

鉴于以下两个类：

@Embeddable
public class CveReferenceId implements java.io.Serializable {

    private String refsource;
    private String refname;
    private String cveid;

    @Column(name = "refsource", nullable = false)
    public String getRefsource() {return this.refsource;}
    public void setRefsource(String refsource) {this.refsource = refsource;}

    @Column(name = "refname", nullable = false)
    public String getRefname() {return this.refname;}
    public void setRefname(String refname) {this.refname = refname;}

    @Column(name = "cveid", nullable = false)
    public String getCveid() {return this.cveid;}
    public void setCveid(String cveid) {this.cveid = cveid;}
}

@Entity
@Table(name = "cve_reference")
@Immutable
public class CveReference implements java.io.Serializable {

    private CveReferenceId id;

    @EmbeddedId
    @AttributeOverrides({
        @AttributeOverride(name = "refsource", column = @Column(name = "refsource", nullable = false)),
        @AttributeOverride(name = "refname", column = @Column(name = "refname", nullable = false)),
        @AttributeOverride(name = "cveid", column = @Column(name = "cveid", nullable = false))})
    public CveReferenceId getId() {return this.id;}
    public void setId(CveReferenceId id) {this.id = id;}
}

当我尝试执行以下代码来检索CVE引用列表时，我得到'不是关联：id.cveid'：

Session session = HibernateUtil.getSession();
Criteria criteria = session.createCriteria(CveReference.class)
    .createAlias("id.cveid", "refid")
    .add(Restrictions.eq("refid", "CVE-2013-1950"));
List<CveReference> refs = criteria.list();

当我运行以下代码时，我得到'不能直接在组件上创建Criteria对象。在拥有实体上创建条件并使用点属性访问组件属性'：

Session session = HibernateUtil.getSession();
Criteria criteria = session.createCriteria(CveReference.class)
    .createAlias("id", "ref")
    .add(Restrictions.eq("ref.id", "CVE-2013-1950"));
List<CveReference> refs = criteria.list();

对于我在这里缺少的任何提示将不胜感激。

- 杰里米

Answer 1

我找到了问题的答案。显然，生成的注释不正确，我需要使用@IdClass。以下作品：

@Entity
@Table(name = "cve_reference")
@IdClass(CveReferenceId.class)
@Immutable
public class CveReference implements java.io.Serializable {

    private String refsource;
    private String refname;
    private String cveid;

    public CveReference() {
    }

    public CveReference(String refsource, String refname, String cveid) {
        this.refsource = refsource;
        this.refname = refname;
        this.cveid = cveid;
    }

    @Id
    @Column(name = "refsource", nullable = false)
    public String getRefsource() {
        return this.refsource;
    }

    public void setRefsource(String refsource) {
        this.refsource = refsource;
    }

    @Id
    @Column(name = "refname", nullable = false)
    public String getRefname() {
        return this.refname;
    }

    public void setRefname(String refname) {
        this.refname = refname;
    }

    @Id
    @Column(name = "cveid", nullable = false)
    public String getCveid() {
        return this.cveid;
    }

    public void setCveid(String cveid) {
        this.cveid = cveid;
    }
}


public class CveReferenceId implements java.io.Serializable {

    private String refsource;
    private String refname;
    private String cveid;

    public CveReferenceId() {
    }

    public CveReferenceId(String refsource, String refname, String cveid) {
        this.refsource = refsource;
        this.refname = refname;
        this.cveid = cveid;
    }

    public String getRefsource() {
        return this.refsource;
    }

    public void setRefsource(String refsource) {
        this.refsource = refsource;
    }

    public String getRefname() {
        return this.refname;
    }

    public void setRefname(String refname) {
        this.refname = refname;
    }

    public String getCveid() {
        return this.cveid;
    }

    public void setCveid(String cveid) {
        this.cveid = cveid;
    }
}

然后按如下方式创建标准：

Session session = HibernateUtil.getSession();
Criteria criteria = session.createCriteria(CveReference.class)
    .add(Restrictions.eq("cveid", "CVE-2013-1950"));
List<CveReference> refs = criteria.list();

无法直接在组件上创建Hibernate Criteria对象

1 个答案: