我正在尝试为一个具有@NamedNativeQuery
个值为@ConstructorResult
的字段的类创建一个Set
的{{1}}。
兽医JPA.java:
enum
Veterinarian.java:
@Entity
@Table(name = "veterinarians")
@Setter
@Getter
@NoArgsConstructor
@NamedNativeQueries({
@NamedNativeQuery(
name = VeterinarianJPA.FIND_ALL_VETS,
query = "SELECT v.id, v.name, vs.specialisations " +
"FROM veterinarians v " +
"JOIN veterinarian_specialisations vs ON v.id = vs.vet_id",
resultSetMapping = VeterinarianJPA.VETERINARIAN_RESULT_MAPPER
)})
@SqlResultSetMappings({
@SqlResultSetMapping(
name = VeterinarianJPA.VETERINARIAN_RESULT_MAPPER,
classes = @ConstructorResult(
targetClass = Veterinarian.class,
columns = {
@ColumnResult(name = "id", type = Long.class),
@ColumnResult(name = "name"),
@ColumnResult(name = "specialisations", type = Set.class)
}
)
)})
class VeterinarianJPA {
static final String FIND_ALL_VETS = "net.kemitix.naolo.gateway.data.jpa.findAllVets";
static final String VETERINARIAN_RESULT_MAPPER = "net.kemitix.naolo.gateway.data.jpa.Veterinarian";
@Id
@GeneratedValue
private Long id;
private String name;
@ElementCollection
@Enumerated(EnumType.STRING)
@CollectionTable(
name = "veterinarian_specialisations",
joinColumns = @JoinColumn(name = "vet_id")
)
private final Set<VetSpecialisation> specialisations = new HashSet<>();
}
VetSpecialisation.java:
public final class Veterinarian {
private Long id;
private String name;
private Set<VetSpecialisation> specialisations;
public Veterinarian() {
}
public Veterinarian(final long id,
final String name,
final Set<VetSpecialisation> specialisations) {
this.id = id;
this.name = name;
this.specialisations = new HashSet<>(specialisations);
}
public long getId() {
return id;
}
public String getName() {
return name;
}
public Set<VetSpecialisation> getSpecialisations() {
return new HashSet<>(specialisations);
}
}
当我尝试执行命名查询时:
public enum VetSpecialisation {
RADIOLOGY,
DENTISTRY,
SURGERY
}
我收到以下异常:
entityManager.createNamedQuery(VeterinarianJPA.FIND_ALL_VETS, Veterinarian.class)
.getResultStream()
我希望SQL为多值java.lang.IllegalArgumentException: Could not locate appropriate constructor on class : net.kemitix.naolo.entities.Veterinarian
at org.hibernate.loader.custom.ConstructorResultColumnProcessor.resolveConstructor(ConstructorResultColumnProcessor.java:92)
at org.hibernate.loader.custom.ConstructorResultColumnProcessor.performDiscovery(ConstructorResultColumnProcessor.java:45)
at org.hibernate.loader.custom.CustomLoader.autoDiscoverTypes(CustomLoader.java:494)
at org.hibernate.loader.Loader.processResultSet(Loader.java:2213)
at org.hibernate.loader.Loader.getResultSet(Loader.java:2169)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1930)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1892)
at org.hibernate.loader.Loader.scroll(Loader.java:2765)
at org.hibernate.loader.custom.CustomLoader.scroll(CustomLoader.java:383)
at org.hibernate.internal.SessionImpl.scrollCustomQuery(SessionImpl.java:2198)
at org.hibernate.internal.AbstractSharedSessionContract.scroll(AbstractSharedSessionContract.java:1058)
at org.hibernate.query.internal.NativeQueryImpl.doScroll(NativeQueryImpl.java:217)
at org.hibernate.query.internal.AbstractProducedQuery.scroll(AbstractProducedQuery.java:1462)
at org.hibernate.query.internal.AbstractProducedQuery.stream(AbstractProducedQuery.java:1486)
at org.hibernate.query.Query.getResultStream(Query.java:1110)
返回多个行,而不是单个值,这将导致构造函数不匹配。如何更改SQL以向构造函数产生正确的输入,还是需要进行其他配置更改?
答案 0 :(得分:0)
好吧,我不确定您是否可以做到这一点。但是您可以使用某种分隔符在LISTAGG
表上使用specialisations
函数将specialisations
与veterinarians
内联。
因此查询应如下所示:
SELECT v.id, v.name
(SELECT LISTAGG(vs.type, ';')
WITHIN GROUP (ORDER BY vs.type)
FROM veterinarian_specialisations vs
WHERE vs.vet_id = v.id) specialisations
FROM veterinarians v;
查询将返回兽医及其分号分隔的专业:
1 NAME DENTISTRY;RADIOLOGY
然后在您的Veterinarian
类构造函数中,必须将String结果重新映射回VetSpecialisation
的Set中。我使用Java 8流api只是为了方便。
public final class Veterinarian {
private Long id;
private String name;
private Set<VetSpecialisation> specialisations;
public Veterinarian() {
}
public Veterinarian(final long id,
final String name,
final String specialisations) {
this.id = id;
this.name = name;
this.specialisations = Arrays.asList(specialisations.split(";"))
.stream()
.map(VetSpecialisation::valueOf) //Map string to VetSpecialisation enum.
.collect(Collectors.toSet());
}