Ids for this class must be manually assigned before calling save on String ID

Question

Already read lots of questions about the same issue, but I still not be able to solve this problem.

I need to have a String primary key on my database.

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class MyClass {

    @Id
    private String myId;
    private String name;

    // getters and setters..

}

The problem is that, if I use String type in a @Id annotated field, Hibernate throws an exception when I try to save the object.

ids for this class must be manually assigned before calling 

And yes, I'm setting a value to the field.

Workarounds I found:

1. Add @GeneratedValue annotation to the field - not worked
2. Change the field type to Integer - it's not feasible for me
3. Add a constructor that receives myId as parameter public MyClass(String myId){ ... } - not worked
4. Use UUID - i can't, cause this id is set by a field that comes in with a POST request.

None of these workarounds worked for me.

UPDATE

I'm using Spring Boot and Spring Data JPA.

How do I insert:

I have an @PostMapping annotated method which handles POST request and call a service that do some business logic and call my repository for persisting.

The request I post:

{
    "myId": "myId",
    "name": "myName"
}

MyService.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class MyService {

    @Autowired
    private MyRepository myRepository;

    public MyClass save(MyClass myClass) {
        return myRepository.save(myClass); // save() should persist my object into the database
    }
}

Reticulum

Answer 1

try this approach

@Entity
public class MyClass{

    @Id
    @GeneratedValue(generator = “UUID”)
    @GenericGenerator(
        name = “UUID”,
        strategy = “org.hibernate.id.UUIDGenerator”,
    )
    @Column(name = “id”, updatable = false, nullable = false)
    private UUID id;

    …
}

======================================

I invoke like this and in my envirenment all work fine:

@Autowired
private EntityManager entityManager;

@PostMapping("")
@Transactional
public void add(@RequestBody MyClass myClass){
        entityManager.persist(myClass);
}

and requst send by post with body:

{
    "myId" : "213b2bbb1"
}

Christ

I cannot use UUID. This primary key is set by a field which comes in a POST request. – Reticulum

@MatheusCirillo ok, try only add @GeneratedValue(strategy=GenerationType.AUTO) for private String myId; – Christ

Unfortunately, other errors raises. "Unknown integral data type for ids : java.lang.String; nested exception is org.hibernate.id.IdentifierGenerationException: Unknown integral data type for ids : java.lang.String" – Reticulum

@MatheusCirillo my question, how do you insert record ? do you use entityManager.persist ? – Christ

Make sure you send myId as not null – Christ

I'm using Spring Data JPA. Question updated describing how I persist data. – Reticulum

change to entityManager.persist(myClass) and make sure myId is not null, it should works – Christ

Answer 2

Based on the helpful answer by @PiotrRogowski, for numeric primary keys, for example those mapped to java.lang.Long:

@Entity
@Table(name = "myclass")
public class MyClass {
    @Id
    @GeneratedValue(generator = "Incremental")
    @GenericGenerator(
        name = "Incremental",
        strategy = "org.hibernate.id.IncrementGenerator",
    )
    @Column(name = "id", updatable = false, nullable = false, insertable = false, unique = true)
    private Long id;
        
    …
}

---

You can invoke it this way:

@Autowired
private EntityManager entityManager;
    
@PostMapping("")
@Transactional
public void add(@RequestBody MyClass myClass) {
    entityManager.persist(myClass);
}

Maura

Answer 3

I faced this problem, turns out I was missing the setter for the id field. Make sure the setter method for the ID is defined in the entity class.

Exhalation

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