hibernate 主键序列问题

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">




hos_user_seq

    </id>
    <property name="name" type="java.lang.String">
        <column name="uname"/>
    </property>
    <property name="password" type="java.lang.String">
        <column name="upassword"/>
    </property>
    <!--省略其他配置-->
</class>

//text

Configuration conf = null;
SessionFactory sessionFactory = null;
Session session = null;
Transaction tx = null;
try {
conf = new Configuration().configure();
sessionFactory = conf.buildSessionFactory();
session = sessionFactory.openSession();

tx = session.beginTransaction();
User u=new User();
// u.setId(1);
u.setName("WWW");
u.setPassword("WWW");
Session sessio =(Session) session.save(u);
System.out.println(sessio);
tx.commit();
} catch (HibernateException e) {
tx.rollback(); //回滚
e.printStackTrace();//注销
} finally{
session.close();

sessionFactory.close();
}

id标签里面怎么没东西？