使用 Enum 和 JPA Repository 的查询方法

Question

我有实体 Driver 和枚举 DriverLanguage。我想通过存储库方法中的参数获取可以说所选语言的驱动程序列表。

...
@Entity
public class Driver{

private Long id;
private firstName;

@ElementCollection(targetClass = DriverLanguage.class)
@Enumerated(EnumType.STRING)
@CollectionTable(name = "driver_language",
    joinColumns = @JoinColumn(name = "driver_language_id"))
@Column(name = "driver_language")
private Set<DriverLanguage> languages = new HashSet<>();
}

public enum DriverLanguage {
  ENGLISH,
  GERMAN
}

现在我正在使用@Query 方法。

我的第一个方法：

@Repository
public interface DriverRepository extends JpaRepository<Driver, Long> {
  @Query("SELECT d "
      + "FROM Driver d "
      + "JOIN DriverLanguage dl on d.id = dl.driver_language_id "
      + "WHERE dl.driver_language = ?1")
    List<Driver> findByLanguage(String language);
}
ERROR: Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: Path expected for join!

然后我读到也许我不应该使用 JOIN，所以我尝试了这个：

@Repository
public interface DriverRepository extends JpaRepository<Driver, Long> {
  @Query("SELECT d "
      + "FROM Driver d, DriverLanguage dl "
      + "WHERE d.id = dl.driver_language_id AND dl.driver_language = ?1")
    List<Driver> findByLanguage(String language);
}
ERROR: Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: DriverLanguage is not mapped

我在这里缺少什么？

Answer 1

直截了当的 JPQL 查询可以是

@Repository
public interface DriverRepository extends JpaRepository<Driver, Long> {

    @Query("SELECT d "
      + "FROM Driver d "
      + "WHERE ?1 MEMBER OF d.languages")
    List<Driver> findByLanguage(DriverLanguage language);
}

错误消息告诉您：

路径是d.languages（属性名）
DriverLanguage 不是实体

使用 Enum 和 JPA Repository 的查询方法

Query method with Enum and JPA Repository

java

jpa

spring-data-jpa

spring-boot