QueryDSL filtering on set

问题

Im having trouble using QueryDSL to filter with the below entities:

@Entity
@Table(name = "newidea")
@Cacheable(true)
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class NewIdea extends DomainObject implements Membership {

    //id, other attributes etc

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "key.idea", cascade = CascadeType.ALL, orphanRemoval = true)
    @QueryInit("newIdeaParticipations.key.student")
    private Set<NewIdeaParticipation> newIdeaParticipations = new HashSet<NewIdeaParticipation>();

    //constructor, getters, setters etc

}

@Entity
@Table(name = "newidea_student")
@AssociationOverrides({
        @AssociationOverride(name = "key.student", 
            joinColumns = @JoinColumn(name = "role_id")),
        @AssociationOverride(name = "key.idea", 
            joinColumns = @JoinColumn(name = "idea_id")) })
public class NewIdeaParticipation implements Serializable {

    @EmbeddedId
    @QueryInit("student")
    private NewIdeaParticipationId key = new NewIdeaParticipationId();

    //other attributes, constructor, getters, setters etc

}

@Embeddable
public class NewIdeaParticipationId implements Serializable {

    @ManyToOne
    private Student student;

    @ManyToOne
    private NewIdea idea;

}

The filters:

    private BooleanExpression authorFilter(Student author){
//        return QNewIdea.newIdea.newIdeaParticipations.any().key.student.eq(author); //NPE any is not null, but any.students attributes is null, and any.key.student is null
//        return QNewIdea.newIdea.newIdeaParticipations.any().user.eq(author.getUser()); //hibernate.QueryException (any is null)
    }

Top query exception:

http://pastebin.com/Vr8gxM7P

Bottom query exception:

http://pastebin.com/sdjMJcmx

What am I doing wrong? Am I missing something?

回答1:

The top query exception is caused by Querydsl's limited path initialization.

The path initialization is documented here http://www.querydsl.com/static/querydsl/3.2.2/reference/html/ch03s03.html#d0e1831

Concerning the second exception: Is the user property properly mapped?

回答2:

After updating to QueryDSL 3.2.3 the issue has been resolved and the below code works. (note the lack of @QueryInit annotations)

//idea class
public class NewIdea extends DomainObject implements Membership {
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "key.idea", cascade = CascadeType.ALL, orphanRemoval = true)
    private Set<NewIdeaParticipation> newIdeaParticipations = new HashSet<NewIdeaParticipation>();
}

//participation class
@Entity
@Table(name = "newidea_student")
@AssociationOverrides({
        @AssociationOverride(name = "key.student",
                joinColumns = @JoinColumn(name = "role_id")),
        @AssociationOverride(name = "key.idea",
                joinColumns = @JoinColumn(name = "idea_id")) })
public class NewIdeaParticipation implements Serializable {
    @EmbeddedId
    private NewIdeaParticipationId key = new NewIdeaParticipationId();
}

//id class
@Embeddable
public class NewIdeaParticipationId implements Serializable {
    @ManyToOne
    private Student student;
    @ManyToOne
    private NewIdea idea;
}

//student class
public class Student extends Role {
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "key.student", cascade=CascadeType.ALL, orphanRemoval=true)
    private Set<NewIdeaParticipation> newIdeaParticipations = new HashSet<NewIdeaParticipation>();
}

//the filter
private BooleanExpression authorFilter(Student author) {
    return QNewIdea.newIdea.newIdeaParticipations.any().key.student.eq(author);
}

来源：https://stackoverflow.com/questions/18347770/querydsl-filtering-on-set

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java

querydsl