Java 在jpa中查询父表时如何从子表中获取字段

我有两个问题表和问题选项。问题有一个复合键。当我通过id查询问题时，如何获得问题选项。如何确保我也能获得问题选项。到现在为止，我只收到了问题。我应该更改映射还是添加一些属性

问题:

@Entity
@Getter
@Setter
@JsonIgnoreProperties({"assessment"})
public class Question implements Serializable {

    @EmbeddedId
    private QuestionAssessmentKey questionAssessmentKey;

    public QuestionAssessmentKey getQuestionAssessmentKey() {
        return questionAssessmentKey;
    }

    public void setQuestionAssessmentKey(QuestionAssessmentKey questionAssessmentKey) {
        this.questionAssessmentKey = questionAssessmentKey;
    }

    @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name =  "assessmentId", insertable = false, updatable = false)
    private Assessment assessment;

    private String questionText;

    private String questionURL;

    private QuestionStatus questionStatus;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumns({
            @JoinColumn(name="assessmentId", referencedColumnName = "assessmentId"),
            @JoinColumn(name="questionNumber", referencedColumnName = "questionNumber")
    })
    private List<QuestionOption> questionOptions;

    public List<QuestionOption> getQuestionOptions() {
        return questionOptions;
    }

    public void setQuestionOptions(List<QuestionOption> questionOptions) {
        this.questionOptions = questionOptions;
    }

    public Assessment getAssessment() {
        return assessment;
    }

    public void setAssessment(Assessment assessment) {
        this.assessment = assessment;
    }
    //    private int questionNumber;
    private QuestionTypes questionType;
//Getters and setters
}

问题评估键

@Embeddable
public class QuestionAssessmentKey implements Serializable {

    private int questionNumber;

    private String assessmentId;
}

---

当然，您不能在一个查询中获取所有数据，因为问题和问题选项之间是一对多关系。但是，当您在获取的

Question

实体上调用

getQuestionOptions

时，它应该加载并返回相应的选项集。

如果只有@ManyToOne映射，那么您可以使用它来完成此fetchType。在@ManyToOne in QuestionOption上急切吗？是的。但这并不能解决您的问题，因为当您通过ID解析QuestionOption实体时，它只会让Hibernate急切地加载相应的问题实体；但是，由于每个问题都可以有多个相应的选项，因此不能采用相反的方法。

@Embeddable
public class QuestionAssessmentKey implements Serializable {

    private int questionNumber;

    private String assessmentId;
}