使用 Oracle Trigger 从序列生成 id 的 HIbernate 问题

We have a before insert trigger that gets the next value from sequence. When the object is persisted with save() method, hibernate gets the value from the sequence and adds it to the object. and when the transaction is committed from Spring's service layer, the ID value is again increased on the database. how do I avoid getting nextval() if the object already has an id..

这就是我想要做的..

用户道

public User saveUser(User user){
      session.getCurrentSession.save(user);//line2
      return user;//line3  
 }

用户服务

public void saveUserAndWriteToAudit(User user, UserAudit userAudit){
  userDao.saveUser(user);//line1
  userAudit.setUserId(user.getId);//line4
  userAudit.saveUserAudit(userAudit);//line5
}

和用户类

 @Entity
  public class User{

     @Id
     @GeneratedValue(strategy=GenerationType.AUTO, generator="a1")
     @SequenceGenerator(name="a1", sequenceName="usersequence")
     private Long id;
     /////////////////
 }

当光标到达第 1 行和第 2 行时，用户对象的 id 属性为空.在第 2 行之后，它具有序列中的 nextval - 比如说 1.在第 4 行上，我已将用户的 id=1 添加到 useraudit 对象中.当在第 5 行之后提交事务时，2 被插入到用户的 id 列中，1 被插入到 UserAudit 的 userId 列中.这对我没有任何意义:(我该如何避免这个问题?谢谢！

create or replace
trigger sa.my_trigger
before insert on sa.my_table
for each row
when (new.id is null)
begin
   select sa.my_sequence.nextval
    into :new.id
    from dual;
end;