SpringDataJPA：使用 Native Query 自定义数据映射

Question

public interface UserRepository extends JpaRepository<User, Long> {

  @Query(value = "SELECT * FROM USERS WHERE EMAIL_ADDRESS = ?0", nativeQuery = true)
  User findByEmailAddress(String emailAddress);
}

假设我有上面的代码，其中我 select * 来自用户。不想这个方法到returnUser对象怎么办。有没有办法可以手动将数据映射到自定义对象 MyUser？我可以在 UserRepository 界面中完成所有这些吗？

谢谢！

Answer 1

你可以这样做

@Query(value = "SELECT YOUR Column1, ColumnN FROM USERS WHERE EMAIL_ADDRESS = ?0", nativeQuery = true)
List<Object[]> findByEmailAddress(String emailAddress);

你必须做映射。也看看 Spring 数据存储库。 Source

Answer 2

What about interface based projection?

基本上，您使用对应于 SQL 查询参数的 getter 编写接口。

通过这种方式，您甚至不需要在投影上强制使用 @Id 参数：

@Entity
public class Book {
     @Id
     private Long id;
     private String title;
     private LocalDate published;
}

public interface BookReportItem {
     int getYear();
     int getMonth();
     long getCount();
}

public interface BookRepository extends Repository<Book, Long> {
     @Query(value = "select " +
                    "  year(b.published) as year," +
                    "  month(b.published) as month," +
                    "  count(b) as count," +
                    " from Book b" +
                    " group by year(b.published), month(b.published)")
     List<BookReportItem> getPerMonthReport();
}

它在当前 Spring 实现中使用下面的 org.springframework.data.jpa.repository.query.AbstractJpaQuery$TupleConverter$TupleBackedMap 作为接口的代理。

它也适用于 nativeQuery = true。

SpringDataJPA：使用 Native Query 自定义数据映射

SpringDataJPA: custom data mapping with Native Query

spring

jpa

spring-data-jpa