誰能說出為什么這個休眠查詢無效？

Question

我有標准查詢，執行該查詢會引發以下異常：

java.lang.IllegalArgumentException: org.hibernate.QueryException: illegal syntax near collection: id [select generatedAlias0.permissions from temp.package.commons.user.Role as generatedAlias0 where generatedAlias0.id=2L]
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1222)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1168)
at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:320)
at org.hibernate.ejb.criteria.CriteriaQueryCompiler.compile(CriteriaQueryCompiler.java:227)
at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:437)
at temp.package.dao.impl.DefaultDAOService.getProperties(DefaultDAOService.java:585)

從代碼框中可以看出，引發錯誤的查詢是：

select generatedAlias0.permissions from temp.package.commons.user.Role as generatedAlias0 where generatedAlias0.id=2L

id屬性是實體的屬性，用@Id @GeneratedValue注釋。 基本上我正在嘗試為id為2的角色對象加載屬性“permissions”，這是一個未初始化的集合.id屬性是long類型。

關於為什么這個查詢會失敗的任何想法？

我可以在此處發布用於創建條件查詢的代碼，但是它相當復雜（因為它是基於LDAP過濾器等生成的），所以我希望從生成的查詢字符串和異常中可以看到錯誤。 如果不是這樣，請告訴我。

后續行動：生成此錯誤的條件查詢是通過以下方式構建的：

EntityManager entityManager = getEntityManager();
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();

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

// queryScopeClass is assigned to type temp.pack.commons.user.Role
Class<? extends T> queryScopeClass = role.getClass();

Root<? extends T> from = criteriaQuery.from(queryScopeClass);

Predicate predicate = criteriaBuilder.equal(from.get("id"), new Long(2));
criteriaQuery.where(predicate);

// attempting to get just the role's permissions
CriteriaQuery<Object> select = criteriaQuery.select(from.get("permissions"));
TypedQuery<Object> typedQuery = entityManager.createQuery(select);

return typedQuery.getResultList();

Role和Permission類已與JPA和一些Hibernate注釋映射，如下所示：

public abstract class Role implements Serializable {

 /**
  * The id of this role. Internal use only.
  * 
  * @since 1.0
  */
 @Id @GeneratedValue
 protected long id;

 /**
  * Set of permissions granted to this role.
  * 
  * @since 1.0
  */
 @OneToMany(cascade = { CascadeType.PERSIST, CascadeType.MERGE }, mappedBy="sourceRole")
 protected Set<Permission> permissions = new HashSet<Permission>();

...

}

public class Permission implements Serializable {
 private static final long serialVersionUID = 1L;

 /**
  * The id of this permission. Used internally for persistence.
  * 
  * @since 1.0
  */
 @Id @GeneratedValue
 @Column(name = "PERMISSION_ID")
 protected long id;

 /**
  * The group to which the owner of this permission is being granted permission to.
  * 
  * @since 1.0
  */
 @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
 @JoinColumn(name = "TARGET_ROLE_ID")
 @ForeignKey(name = "FK_TARGET_GROUP_PERMISSION_ID",
   inverseName = "FK_PERMISSION_ID_TARGET_GROUP")
 protected Group targetGroup;

 /**
  * The role that has been granted this permission.
  * 
  * @since 1.0
  */
 @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
 @JoinColumn(name = "SOURCE_ROLE_ID")
 @ForeignKey(name = "FK_SOURCE_GROUP", inverseName = "FK_GROUP_PERMISSIONS")
 private Role sourceRole;

...

}

我期待對typedQuery.getResultList（）的調用返回僅包含一個元素的集合列表：ID = 2的角色的權限對象的集合。這是嘗試從對象中僅選擇“ permissions”集合id = 2的角色。

我是標准查詢的新手，我很難找到它的錯誤。

Answer 1

沒有更多信息，聽起來你正在嘗試做類似的事情：

select rp
from Role r
inner join r.permissions rp
where r.id = 2

您可以發布帶注釋的實體和條件示例嗎？