带有投影的Spring JPA本机查询提供“ConverterNotFoundException”

Question

org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [org.springframework.data.jpa.repository.query.AbstractJpaQuery$TupleConverter$TupleBackedMap] to type [com.example.IdsOnly]

import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@Entity
@Table(name = "TestTable")
public class TestTable {

    @Id
    @Basic(optional = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    @Column(name = "Id")
    private Integer id;
    @Column(name = "OtherId")
    private String otherId;
    @Column(name = "CreationDate")
    @Temporal(TemporalType.TIMESTAMP)
    private Date creationDate;
    @Column(name = "Type")
    private Integer type;
}

import lombok.Value;

@Value // This annotation fills in the "hashCode" and "equals" methods, plus the all-arguments constructor
public class IdsOnly {

    private final Integer id;
    private final String otherId;
}

public interface TestTableRepository extends JpaRepository<TestTable, Integer> {

    @Query(value = "select Id, OtherId from TestTable where CreationDate > ?1 and Type in (?2)", nativeQuery = true)
    public Collection<IdsOnly> findEntriesAfterDate(Date creationDate, List<Integer> types);
}

@Autowired
TestTableRepository ttRepo;
...
    Date theDate = ...
    List<Integer> theListOfTypes = ...
    ...
    Collection<IdsOnly> results = ttRepo.findEntriesAfterDate(theDate, theListOfTypes);  

谢谢你的帮助。我真的不明白我做错了什么。

Answer 1

使用spring数据，您可以省略中间人，并简单地定义

public interface IdsOnly {
  Integer getId();
  String getOtherId();
}

并使用本机查询,如；

@Query(value = "Id, OtherId from TestTable where CreationDate > ?1 and Type in (?2)", nativeQuery = true)
    public Collection<IdsOnly> findEntriesAfterDate(Date creationDate, List<Integer> types);

查看https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#投影