複合ID及其在JPA

Question

代我想使用自定義的類象ID

@javax.persistence.Embeddable 
class ObjectID impements Serializable{ 
private Long value;  
    //setters, getters and other 
} 

這裏被映射類

@Entity 
@IdClass(ObjectID.class) 
public class Country implements Serializable 
{ 
    @Id 
    @AttributeOverride(name = "value", column = @Column(name = "id")) 
    @SequenceGenerator(name = "CountrySequenceGenerator", 
         sequenceName = "lab_country_seq") 
    @GeneratedValue(strategy = GenerationType.SEQUENCE, 
        generator = "CountryCountryGenerator") 
    private ObjectID value; 
    // setters, getters, fields 
} 

不工作。沒有產生價值。任何想法，我怎樣才能生成複合ID的ID？

Answer 1

Id類必須是Serializable並實現hashCode並等於