Question

（以下不是我的实际实体，但结构类似）

我目前正在尝试编写一个控制器方法，该方法返回给定提供者的收件人页面。

Provider类看起来像这样：

@Entity
@Table(name="Provider")
public class Provider {
    @Id @GeneratedValue
    public Long id;

    @Column(name="joinDate")
    @Type(type="org.jadira.usertype.dateandtime.joda.PersistentDateTime")
    public DateTime joinDate;

    @ElementCollection(fetch=FetchType.LAZY)
    @OneToMany
    @JoinTable(
            name="Provider_Recipients",
            joinColumns=@JoinColumn(name="providerId"),
            inverseJoinColumns=@JoinColumn(name="recipientId"))
    public Collection<Recipient> recipients;

    public Provider() {
    }
}

收件人类看起来像这样：

@Entity
@Table(name="Recipients")
public class Recipient {
    @Id @GeneratedValue
    public Long id;

    @ElementCollection(fetch=FetchType.EAGER)
    @MapKeyColumn(name="type")
    @Column(name="value")
    @CollectionTable(
            name="Recipient_ProtoAttrs",
            joinColumns = @JoinColumn(name="recipientId"))
    public Map<String, String> attributes;

    public Long quantity;

    @Column(name="date")
   @Type(type="org.jadira.usertype.dateandtime.joda.PersistentDateTime")
    public DateTime date;

    public Recipient() {
        this.attributes = new HashMap<>();
    }

    public Recipient(Recipient old) {
         this.attributes = new HashMap<>(old.attributes);
         this.quantity = old.quantity;
         this.date = old.date;
    }
}

我正在使用Provider表和Recipients表之间的映射表。

Repository的findAll方法：

@Override
public Page<T> findAll(Predicate predicate, Pageable pageable) {

    JPQLQuery countQuery = createQuery(predicate);
    JPQLQuery query = querydsl.applyPagination(pageable, createQuery(predicate));

    Long total = countQuery.count();
    List<T> content = total > pageable.getOffset() ? query.list(path) : Collections.<T> emptyList();

    return new PageImpl<>(content, pageable, total);
}

现在问题。尝试以下查询时：

QProvider qProvider = QProvider.provider;
QRecipient qRecipient = QRecipient.recipient;
BooleanExpression exp = qRecipient.in(qProvider.recipients).and(qProvider.id.eq(providerId));
return providerRepo.findAll(exp, new PageRequest(pageNum, PAGE_SIZE));

我得到了

Undeclared path 'provider'. Add this path as a source to the query to be able to reference it.

如果我改为尝试：

QProvider qProvider = QProvider.provider;
QRecipient qRecipient = QRecipient.recipient;
BooleanExpression exp = qRecipient.in((CollectionExpression) new JPASubQuery()
    .from(qProvider)
    .where(qProvider.id.eq(providerId))
    .list(qProvider.recipients));
return providerRepo.findAll(exp, new PageRequest(pageNum, PAGE_SIZE));

然后我得到一个SQL语法错误。具体来说，生成的子查询是

select . from Provider provider1_, Provider_Recipients recipients2_, Recipient recipient3_ where provider1_.id=recipients2_.providerId and recipient2_.recipientId=recipient3_.id and provider1_.id=?

我尝试了几种不同的方法来指定查询和子查询，但我总是得到这两个错误中的一个。

有什么建议吗？

Answer 1

找到解决方案。

找到一个解决方法（或者更确切地说，我应该首先采用这种方式）：

而不是：

BooleanExpression exp = qRecipient.in((CollectionExpression) new JPASubQuery()
    .from(qProvider)
    .where(qProvider.id.eq(providerId))
    .list(qProvider.recipients));

这样：

BooleanExpression exp = qRecipient.id.in(new JPASubQuery()
    .from(qProvider).rightJoin(qProvider.recipients, qRecipient)
    .where(qProvider.id.eq(providerId))
    .list(qRecipient.id));

按预期工作。

QueryDSL和Hibernate的未声明路径'provider'/ SQL语法错误

1 个答案: