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

Question

有一种情况，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个实体类，如customer和address，其中name在customer中作为变量，area在address实体类中作为变量

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
.....
.....
.....
}

要将本机查询映射到entity类，可以在entity中提供@SqlResultSetMapping并在nativeQuery中提供映射的名称

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完成

如果我有来自2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

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();

Answer 2

最简单的方法是在本机查询中使用JOIN，如下所示

Native query :- select c.name,a.area from customer c JOIN address a ON c.id = a.custid

因此，您只需在客户实体上提供结果集映射