SpringDataJPA:使用Native Query进行自定义数据映射

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,我从用户那里选择*.如果我不希望此方法返回User对象,该怎么办？有没有办法我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

你可以做这样的事情

@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.看一下Spring Data Repository.资源

Answer 2

基于界面的投影怎么样？

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，您甚至不需要强制@Id投影参数：

@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();
}

它使用org.springframework.data.jpa.repository.query.AbstractJpaQuery$TupleConverter$TupleBackedMap底层作为当前 Spring 实现中的接口代理。

它也适用nativeQuery = true。