Spring 存储库接口：按类型查询方法

Question

我想知道是否可以使用弹簧 query methods 指定特定的子类型。

例如，如果有 MailUser 和 ChatUser，extend User 和 InheritanceType.SINGLE_TABLE - 我能找到所有 MailUser 和 PersonRepository?

或者在多个类 extend User 的情况下，我可以找到所有 User 排除所有 MailUser 吗？

public interface PersonRepository extends Repository<User, Long> {

  List<Person> findByEmailAddressAndLastname(EmailAddress emailAddress, String lastname);
...
}

Answer 1

您不能使用基于方法名称的自动查询创建，Spring数据不支持它（参见here for the supported expressions). However, you can use @Query to specify a JPQL query by hand and use the TYPE(entity) operator in the WHERE clause to narrow down to a particular entity type. See JPA spec 4.6.17.5 实体类型表达式:

An entity type expression can be used to restrict query polymorphism. The TYPE operator returns the exact type of the argument.

[...]

Examples:
SELECT e
FROM Employee e
WHERE TYPE(e) IN (Exempt, Contractor)

SELECT e
FROM Employee e
WHERE TYPE(e) IN (:empType1, :empType2)

SELECT e
FROM Employee e
WHERE TYPE(e) IN :empTypes

SELECT TYPE(e)
FROM Employee e
WHERE TYPE(e) <> Exempt

Spring 存储库接口：按类型查询方法

Spring repository interface: query methods by type

spring

spring-data

spring-data-jpa