Converting hibernate entity to JSON: oblectId instead of whole object

Question

Project has two entities:

@Entity
public class Customer {
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Integer id;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "city_id", nullable = true)
private City city;
...
}

and

@Entity
public class City {
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Integer id;

@Column(name = "name", nullable = false)
private String name;
...
}

Cutomer entity to JSON using Gson or Jackson converts as

{
"id":1,
"city":{"id":1, "name":"New York"}
}

I want it is converts as

{
"id":1,
"city_id":1
}

How I can do that via gson or jackson?

you should use a custom Serializer to achieve this. @Satmurat — Vikrant Kashyap, Apr 02 '16 at 16:28
Please Check my Answer at this Link >[How to use Customize Serializer](https://stackoverflow.com/questions/35592831/should-serialization-logic-be-in-the-entity-or-other-class/35593831#35593831) — Vikrant Kashyap, Apr 02 '16 at 16:32
@VikrantKashyap, writing serializer for each entity is not nice. — Satmurat, Apr 02 '16 at 17:09

score 0 · Answer 1 · edited May 23 '17 at 10:28

This question might be helpful to you.

Gson: How to exclude specific fields from Serialization without annotations

I don't know if there is a direct way to accomplish this, but there are indirect ways in which it can be done. For instance, you could mark private City city as transient, and then you could expose another field called city_id that would simply be the city id. It would look something like this:

@Entity
public class Customer {
    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private Integer id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "city_id", nullable = true)
    private transient City city;

    private int city_id;
    ...
}

Converting hibernate entity to JSON: oblectId instead of whole object

1 Answers1