Java Hibernate-是否在Hashmap中保留Hashmap？

Question

Context: I want users to take an employee screening test where each question is "paired-up" with another question, but the questions are worded differently.

The HashMap below in the User Class only works if it's:

Map<Question, Answer> answers = new HashMap<>();

However, my program would have two different answers going to two similar questions. Any advice as to how I should set up my classes? Would trying to persist a HashMap of a HashMap make sense? Should I have a separate class for MatchingAnswers?

Thanks

@Entity
public class User {

    @Id
    @GeneratedValue
    int id;    

    @OneToMany(mappedBy = "user")
    @MapKeyJoinColumn(name="QUESTION_ID")
    Map<Map<Question, QuestionMatch>,Answer> answers = new HashMap<>();
}

.

@Entity
public class Question {

    @Id
    @GeneratedValue
    private int id;

    @NotNull
    @Size(min = 3, message = "Please add a question")
    private String question1;

    public Integer desiredAnswer1;

    private Boolean matchingOpposite;

    @OneToOne //not sure if this is necessary
    QuestionMatch matchingQuestion; 

.

@Entity
public class Answer {


    @Id
    @GeneratedValue
    private long id;

    private int answer;

    private int matchingAnswer;

    @ManyToOne
    private User user;

    @ManyToOne
    @JoinColumn(name="QUESTION_ID")

    Question question;

.

@Entity
public class QuestionMatch {

    @Id
    @GeneratedValue
    private int id;

    @NotNull
    @Size(min=3, message = "Please add a question")
    private String questionMatch;


    public int desiredAnswerForQuestionMatch;

Answer 1

I'd suggest not using such complicated structures in your entity class. If you have a canonical Question for similar Questions you can add

@OneToOne
Question canonical;

You can create a more suited structure for you in upper layer (like Service).

You also can create a service method that finds similar questions or canonical question. So before add new question, you check if similar question already exists.

Another option is to allow different questions have the same answer. If you don't want to have the same answer be multiple time in the same test just find questions with different answers.