Java enum int值只能与JPA顺序存储吗？

Question

I have a simple enum as follows:

public enum Tax {
    NONE(10), SALES(20), IMPORT(30);

    private final int value;
    private Tax(int value) {
        this.value = value;
    }

    public int getValue() {
        return value;
    }
}


@Entity
public Person {

.........

   private TAX tax = TAX.NONE;
   public TAX getTax() {
      return tax;
   }

   public void setTax(Tax tax) {
      this.tax = tax;
   }

.............
}

When saving a Person object in database via JPA, the value saved in the database is 0 for the object's tax field with the value being TAX.NONE.

Why not 10 saved in the database? How can I let JPA save 10 for TAX.NONE in database via JPA?

Thanks!

Answer 1

JPA stores the identity of the enum value in the database, either its index (ordinal) or its name (string). There's no built-in way to retrieve the correct enum instance from a field on the enum, and multiple instances could have the same field value. If you really want to store a secondary field value in the database, you could write your own converter for your persistence provider.