How to distinguish between null and not provided values for partial updates in Spring Rest Controller

Question

I\'m trying to distinguish between null values and not provided values when partially updating an entity with PUT request method in Spring Rest Controller.

Consider

Answer 1

Use boolean flags as jackson's author recommends.

class PersonDTO {
    private String firstName;
    private boolean isFirstNameDirty;

    public void setFirstName(String firstName){
        this.firstName = firstName;
        this.isFirstNameDirty = true;
    }

    public String getFirstName() {
        return firstName;
    }

    public boolean hasFirstName() {
        return isFirstNameDirty;
    }
}