JPA SqlResultSetMapping 注解无法为非实体执行映射

Question

Spring Boot + JPA/Hibernate 在这里。我使用

EntityManager

进行以下查询：

@Component
public class AnalyticsPersistor {

    @PersistenceContext
    private EntityManager entityManager;

    public List<RevenueRank> fetchRevenuRanks(String clientName) {

        String revRankQuery = "SELECT Id, Higher_Level_Entity_Value as Customer_Name, Revenue, Client_Name," +
            "ROW_NUMBER() OVER(ORDER BY Revenue DESC) CustomerRank " +
            "FROM cooperai.analytics.tbl_master_analytics " +
            "where Client_Name LIKE CONCAT('%', :clientName,'%');";

        Query revenueRankQuery = entityManager.createNativeQuery(revRankQuery, RevenueRank.class);
        revenueRankQuery.setParameter("clientName", clientName);

        return revenueRankQuery.getResultList();

    }
}

我正在尝试使用

@SqlResultSetMapping

将此查询的结果映射回

List<RevenueRank>

（重要的是要注意

RevenueRank

不是由表支持的真正的 JPA 实体我只是汇总来自查询并尝试将它们填充到我称为

RevenueRank

的 POJO 中）：

@SqlResultSetMapping(
    name="RevenueRankResult",
    entities={
        @EntityResult(
            entityClass = RevenueRank.class,
            fields= {
                @FieldResult(name="Id", column="id"),
                @FieldResult(name="Customer_Name", column="customer_name"),
                @FieldResult(name="Revenue", column="revenue"),
                @FieldResult(name="Client_Name", column="clientName"),
                @FieldResult(name="CustomerRank", column="customerRank")
            }
        )
    }
)
@Data
public class RevenueRank {

    @Id
    private Long id;
    private String customerName;
    private BigDecimal revenue;
    private String clientName;
    private Integer customerRank;

}

当我构建并运行 Spring Boot 应用程序并点击调用此

AnalyticsPersistor#fetchRevenuRanks(String)

方法的 API 端点时，我得到：

org.hibernate.MappingException: Unknown entity: com.me.myapp.RevenueRank

好的。所以也许我只需要将

RevenueRank

指定为

@Entity

？但是当我尝试将

@Entity

添加到

RevenueRank

类时，我得到：

org.hibernate.exception.GenericJDBCException: could not execute query

谁能发现我哪里出错了？ 我只需要将这个本机查询的结果映射到我的

RevenueRank

POJO 列表。

Answer 1

@EntityResult

只能用于实体。要将结果映射到 POJO ，您需要使用

@ConstructorResult

。所以请尝试以下操作：

@SqlResultSetMapping(
    name="RevenueRankResult",
    classes={
        @@ConstructorResult(
            targetClass = RevenueRank.class,
            columns= {
                @ColumnResult(name = "Id"),
                @ColumnResult(name = "Customer_Name"),
                @ColumnResult(name = "Revenue"),
                @ColumnResult(name = "Client_Name"),
                @ColumnResult(name = "CustomerRank")
            }
        )
    }
)
@Data
public class RevenueRank {

    @Id
    private Long id;
    private String customerName;
    private BigDecimal revenue;
    private String clientName;
    private Integer customerRank;

     public RevenueRank(Long id , String customerName, BigDecimal revenue ,
String clientName,Integer customerRank){
    

    }
}

请注意，

RevenueRank

和

@ColumnResult

中的构造函数参数应该具有相同的顺序。