Ignore property in nested object of the same type with Spring Boot - spring-boot

Question

I have one class which is entity and use the same class as a property:
#Entity
public class Employee {
private String name;
#OneToOne
#JoinColumn(name = "supervisor_id", referencedColumnName = "id")
private Employee supervisor;
//getters and setters
}
I want to get the supervisor of an employee, but not the supervisor of the supervisor. Can I manage this somehow?
{
"name": "PersonName",
"supervisor": {
"name": "Supervisor name",
"supervisor": null // i don't want this one
}
}

Answer 1

In the end I just used nested classes for both - dto and entity with fields needed.
True that I duplicated properties of the classes, but at least it's clean and simple.

Answer 2

Just ignore the nulls in the Json. The following works for me:
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import org.codehaus.jackson.map.annotate.JsonSerialize;
import javax.persistence.*;
#Getter
#Setter
#ToString
#Entity
#JsonSerialize(include = JsonSerialize.Inclusion.NON_EMPTY)
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "supervisor_id", referencedColumnName = "id")
private Employee supervisor;
}
Here's the test
#Test
public void test2() throws Exception {
Employee employee = makeEmployee("employee 1");
Employee supervisor1 = makeEmployee("supervisor 1");
employee.setSupervisor(supervisor1);
Employee save = employeeRepository.save(employee);
System.out.println(new ObjectMapper().writerWithDefaultPrettyPrinter().writeValueAsString(save));
}
Here's my test output:
{
"id" : 1,
"name" : "employee 1",
"supervisor" : {
"id" : 2,
"name" : "supervisor 1"
}
}
Make sure you use the correct JsonSerialize org.codehaus.jackson.map.annotate.JsonSerialize not com.fasterxml.jackson.databind.annotation.JsonSerialize