[英]How to get a HashMap result from Spring Data Repository using JPQL?
我目前已經在User 、 Shop和Role之間使用 Map 實現了三元關系。 所以在我的用戶實體中我有這個映射:
用戶.java
@Entity
@Table(name = "us_users")
public class User implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(nullable = false)
private int id;
@Basic(fetch = FetchType.LAZY, optional = false)
private String uuid;
@NotBlank(message = "First name can not be empty")
@Column(name = "usFname")
private String usFname;
@NotBlank(message = "Username can not be left empty")
@Column(name = "us_lname")
private String usLname;
@NotBlank(message = "Email field can not be empty")
@ValidEmail
@Column(name = "usEmail", unique = true)
@Basic(fetch = FetchType.LAZY, optional = false)
private String usEmail;
//this is the actual mapping
//a user can have a list of shops, but one role assigned for each shop
@ManyToMany
@MapKeyJoinColumn(name = "shop_fk")
@JoinTable(name = "user_shop_role",
joinColumns = @JoinColumn(name = "user_fk"), inverseJoinColumns = @JoinColumn(name = "role_fk"))
private Map<Shop, Role> shopRoleMap = new HashMap<>();
//GETTERS AND SETTERS,
}
角色.java
@Entity
@Table(name = "ro_roles")
public class Role {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(nullable = false)
private int id;
@Column(name = "rn_role_name")
private String roleName;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getRoleName() {
return roleName;
}
public void setRoleName(String roleName) {
this.roleName = roleName;
}
}
店鋪.java
@Entity
@Table(name = "sh_shops")
public class Shop {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(nullable = false)
private int id;
@NotBlank(message = "Shop name can not be left blank")
private String sh_name;
@NotBlank(message = "please provide shop icon")
private String sh_icon;
@NotBlank(message = "please fill the shop description")
private String sh_description;
@NotBlank
private String sh_tag;
//setters, getters, equals, hashCode methods.
}
此映射為我提供了數據庫中的另一個表 ( user_shop_role ),其中包含user_fk 、 shop_fk和role_fk ,這很可愛。 困難的一點是使用 Spring 數據 JPA 進行查詢,並為給定用戶獲得 HashMap 的結果:登錄用戶的 HashMap<Shop,Role>。
在 UserRepository 層我試過這個:
接口UserRepository擴展了 JpaRepository 並且我有這個查詢......
@Query("SELECT u FROM User u join shopRoleMap m where key(m)= usEmail")
public HashMap<Shop, Role> findByUser(String email);
}
我如何獲得使用 Map 集合映射的三元關系的結果,以獲取商店列表和相應的角色值。 更多的關鍵,價值結果?
@Repository
public interface UserRepository
extends JpaRepository<User, Integer> {
@Query("SELECT key(m), value(m) FROM User u join u.shopRoleMap m" +
" where u.usEmail = :email")
List<Object[]> findByUserEmail(String email);
}
select
shop3_.id as id1_1_0_,
role2_.id as id1_0_1_,
shop3_.sh_description as sh_descr2_1_0_,
shop3_.sh_icon as sh_icon3_1_0_,
shop3_.sh_name as sh_name4_1_0_,
shop3_.sh_tag as sh_tag5_1_0_,
role2_.rn_role_name as rn_role_2_0_1_
from
us_users user0_
inner join
user_shop_role shoprolema1_
on user0_.id=shoprolema1_.user_fk
inner join
ro_roles role2_
on shoprolema1_.role_fk=role2_.id
inner join
sh_shops shop3_
on shoprolema1_.shop_fk=shop3_.id
where
user0_.us_email=?
用上面的代碼加上另一種方式更新
Github 回購 - https://github.com/kavi-kanap/stackoverflow-6313585
Spring 數據 JPA 具有稱為屬性表達式的功能,您可以在其中訪問子實體或相關實體
例如
List<Shop> findByUser_email(String email);
有關更多詳細信息,請參閱此
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