Java JPA - I need to auto generate value of field other than id

Question

I'm working on employees database. Each one of them needs to have it's unique employee number in 5 digit format. It doesn't have to, but can be corelated with id number in database. I was trying to create custom seter that will add auto generated id to number 00000, but it didn't worked. Now I'm trying to set @SequenceGenerator, but it doesn't work to.

the entity looks like this:

@Entity
@Table(name = "employees")
@NoArgsConstructor
@SequenceGenerator(name="empIdGen", initialValue=10, allocationSize=100)
@Data
public class EmployeeEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="empIdGen")
    private int employeeId;
    private String firstName;
    private String lastName;

}

returnet JSON has 0 on that field for each employee:

[
    {
        "id": 1,
        "employeeId": 0,
        "firstName": "Jon1",
        "lastName": "Doe1"
    },
    {
        "id": 2,
        "employeeId": 0,
        "firstName": "Jon2",
        "lastName": "Doe2"
    },
    {
        "id": 3,
        "employeeId": 0,
        "firstName": "Jon3",
        "lastName": "Doe3"
    }
]

I expect values for field "employeeId" like 00001, 00002, 00003 or completly random, but unique. I would appreciate suggestions how to do that.