求hibernate达人帮忙解决一下复合主键中一个字段自增有关问题

@Entity@IdClass(GirlPK.class)public class Girl{    private int id;    private String name;    private int age;        @Id    @GeneratedValue(strategy=GenerationType.IDENTITY)    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    @Id    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    }

public class GirlPK implements Serializable {    private static final long serialVersionUID = 1L;    private int id;    private String name;        public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public boolean equal(Object obj){        if(this == obj){            return true;        }        if(obj != null && obj.getClass() == GirlPK.class){            GirlPK target = (GirlPK)obj;            if(target.getId() == getId() && target.getName().equals(getName())){                return true;            }        }        return false;    }    public int hashCode(){        return getId()*7+getName().hashCode();    }        

public class Test {    private static SessionFactory sessionFactory;    private static ServiceRegistry serviceRegistry;    public static void main(String[] args) {        GirlPK gpk = new GirlPK();        Girl g = new Girl();        g.setAge(23);        Configuration config = new Configuration().configure(); // 读取hibernate配置文件        serviceRegistry = new ServiceRegistryBuilder().applySettings(                config.getProperties()).buildServiceRegistry();        sessionFactory = config.buildSessionFactory(serviceRegistry); // 创建SessionFactory        Session session = sessionFactory.openSession();        session.beginTransaction();        session.save(g);        session.flush();        session.getTransaction().commit();    }}

 drop table Girl    create table Girl (        id int identity not null,        name varchar(255) not null,        age int not null,        primary key (id, name)    )