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[英]How do I map 1 column of a SINGLE table query to a COLLECTION using Spring JPA/Hibernate
[英]How do I solve this Hibernate JPA query?
我正在尝试使用标准构建器构建查询。
object 结构就像这个 User -> 有一个名为“userRoles”的列表...userRoles 包含 class UserRoleEntity 的对象。
每个 UserRoleEntity 都有一个 RoleEntity。
每个 RoleEntity 都有一个我要过滤的“名称”。
所以我现在的查询:
ListJoin<UserEntity, UserRoleEntity> userRoles = user.joinList("userRoles", JoinType.INNER);
predicates.add(userRoles.get("role").<RoleEntity> get("name").in("abc"));
但它不起作用......有什么建议吗?
谢谢。
根据代码片段,很难确定错误的确切原因。
但是,假设这些实体
@Entity
@Table(name="t_user")
public class UserEntity {
@Id
@Column(name="id")
private Integer id;
@Column(name="name")
private String name;
@OneToMany(mappedBy = "user", cascade = CascadeType.ALL, orphanRemoval = true)
List<UserRoleEntity> userRoles;
//...
}
@Entity
@Table(name="t_user_role")
public class UserRoleEntity {
@Id
@Column(name="id")
private Integer id;
@ManyToOne
private UserEntity user;
@OneToOne
@JoinColumn(name = "role_id")
private RoleEntity role;
//...
}
@Entity
@Table(name="t_role")
public class RoleEntity {
@Id
@Column(name="id")
private Integer id;
@Column(name="name")
private String name;
//...
}
自定义存储库上的以下方法
List<UserEntity> findUserByRoleName(String roleName) {
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<UserEntity> cq = cb.createQuery(UserEntity.class);
Root<UserEntity> root = cq.from(UserEntity.class);
Join<Object, Object> joinUserRole = root.join("userRoles");
Join<Object, Object> joinRole = joinUserRole.join("role");
Predicate predicateRoleName = cb.equal(joinRole.get("name"), roleName);
cq.where(predicateRoleName);
TypedQuery<UserEntity> query = entityManager.createQuery(cq);
return query.getResultList();
}
生成所需的查询:
select userentity0_.id as id1_2_, userentity0_.name as name2_2_
from t_user userentity0_
inner join t_user_role userroles1_ on userentity0_.id=userroles1_.user_id
inner join t_role roleentity2_ on userroles1_.role_id=roleentity2_.id
where roleentity2_.name=?
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