NativeQuery映射和@SqlResultSetMapping以及多个@Entity类，是否可能？

Question

有一种情况是，我有一个本机查询，其中包含两个实体类的数据，如何通过@SqlResultSetMapping将该数据映射到实体类？例如

Native query:- select customer.name, address.area from customer, address where customer.id=address.custid;

2实体类，如客户和地址，名称作为客户中的变量，区域作为地址实体类中的变量。

Customer class:
@Entity
public class Customer {
    @Id
    private String name;
    getters and setters
.....
.....
.....
}

Address Class entity:
@Entity
public class Address{
    @Id
    private String area;
    getters and setters
.....
.....
.....
}

要将本机查询与实体类映射，可以通过在实体中给出@SqlResultSetMap并在nativeQuery中给出映射的名称来完成

Query query = entityManager.createNativeQuery(sbQuery, "checkInfoMapping");

它将检查映射名称并映射到相应的实体类，这可以针对单个实体类来完成。

如果我有来自两个实体类的本机查询的数据，可以这样做吗？如果是，我如何将其映射到具有本机查询的实体类？

Answer 1

最简单的方法是在本机查询中使用JOIN，如下所示。

Native query:-在c.id=a.custid上从客户c加入地址a中选择c.name，a.area

因此，您必须在客户实体上提供结果集映射。

Answer 2

你应该这样做：

@SqlResultSetMapping(
   name = "checkInfoMapping",
   classes = {
      @ConstructorResult(targetClass = ResultInfo.class,
         columns = {
            @ColumnResult(name = "cust_name", type = String.class),
            @ColumnResult(name = "adr_area", type = String.class)
         }
      )
   }
)
@Entity
@Table(name = "TST_CUSTOMER")
public class Customer {

    @Id
    @Column(name = "cust_id")
    private Long id;

    @Column(name = "cust_name")
    private String name;

    ...
}


@Entity
@Table(name = "TST_ADDRESS")
public class Address{

    @Column(name = "adr_area")
    private String area;

    @ManyToOne
    @JoinColumn(name = "adr_cust_id")
    private Customer customer;
    ...
}

// this is not entity, just dto class
public class ResultInfo
{
   private String name;
   private String area;

   public ResultInfo(String name, String area)
   {
      this.name = name;
      this.area = area;
   }
   // ...
}

问题是：

List<ResultInfo> resultList = entityManager.createNativeQuery(
   "select cust_name, adr_area from TST_CUSTOMER, TST_ADDRESS where TST_CUSTOMER.cust_id = TST_ADDRESS.adr_cust_id",
   "checkInfoMapping")
   .getResultList();