CODEWITHSUNDEEP
javahibernatespring-boot
user8689774
user8689774

Reputation:

Hibernate OneToMany and ManyToOne error in mapping

I have an entity called User with these fields :

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "user_id")
private Long id;    

@Column(name = "name")
private String name;

@Column(name = "last_name")
private String lastName;

@OneToMany(mappedBy="userId")   
private List<Survey> survey= new ArrayList<>();

And the Survey entity which has :

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "SURVEY_ID")
private Long Id;

@ManyToOne
@JoinColumn(name = "user_id",referencedColumnName="user_id")
private User userId;
.....

I want one User to be have many Surveys, and each survey is related to one user. But there is something wrong with the way I've mapped it, cuz as JSON file, when I access allUsers I get this :

[{"id":1,"name":"User","lastName":"user","email":"[email protected]","surveyData":[{"userId":{"id":1,"name":"User","lastName":"user","email":"[email protected]","surveyData": ,...... and repeats itself

So instead of getting as list the values of the survey data, I get the values of the Users information ? Can someone help me with this ?

Upvotes: 1

Views: 460

Answers (1)

Mathias G.
Mathias G.

Reputation: 5105

Your mapping is correct.

Just use @JsonManagedReference in your User class and @JsonBackReference in your Survey Class. @JsonManagedReference is the forward part of reference – the one that gets serialized normally. @JsonBackReference is the back part of reference – it will be omitted from serialization.

In the User Class:

@OneToMany(mappedBy="userId")
@JsonManagedReference  
private List<Survey> survey;

In the Survey Class:

@ManyToOne
@JoinColumn(name = "user_id",referencedColumnName="user_id")
@JsonBackReference
private User userId;

I have 2 remarks:

  • If the surveys are not ordered, you can consider to use a Set instead of a List.
  • I would also recommend to rename the class variable userId in the Survey class to user, since it is a User object and no identifier.

Upvotes: 3

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