小编Jul*_*ger的帖子

在这个问题中,我正在使用Hibernate 4.3.4.Final和Spring ORM 4.1.2.RELEASE.

我有一个User类,它包含一组这样的CardInstances:

@Entity
@Table
public class User implements UserDetails {

    protected List<CardInstance> cards;

    @ManyToMany
    public List<CardInstance> getCards() {
        return cards;
    }

    // setter and other members/methods omitted 
}

@Table
@Entity
@Inheritance
@DiscriminatorColumn(name = "card_type", discriminatorType = DiscriminatorType.STRING)
public abstract class CardInstance<T extends Card> {

    private T card;

    @ManyToOne
    public T getCard() {
        return card;
    }
}

@Table
@Entity
@Inheritance
@DiscriminatorOptions(force = true)
@DiscriminatorColumn(name = "card_type", discriminatorType = DiscriminatorType.STRING)
public abstract class Card {
    // nothing interesting here …