请教Hibernate的Criteria查询的一个小问题

实体类:
public class User implements Serializable
{
private static final long serialVersionUID = 120215L;
private long id;
private String name;
private int age;
private String role;
get...略
set...略

}
查询方法
public static List selectUser(User u,int first,int max)
{
List list = null;
try
{
User user = new User();
BeanUtils.copyProperties(user,u);
Session session = Hibernate.getCurrentSession();
Criteria criteria = session.createCriteria(User.class);
int age = user.getAge();
if(age == 0)
{
user.setAge(0);
criteria.add(Restrictions.sqlRestriction("age<20"));
}

        criteria = criteria.add(Example.create(user));
        if(first == 0 && max == 0)
            list =  criteria.list();
        else
        {
            criteria.setFirstResult(first);
            criteria.setMaxResults(max);
            list =  criteria.list();
        }
    }catch(Exception e)
    {
        log.error(".....");
        log.error(e);
        e.printStackTrace();
    }
    finally
    {
        Hibernate.closeSession();
    }

    return list;
}

生成的查询语句总跟着个...and (this.age=?) ,请问怎样去掉默认的age=0

[code="java"]
criteria = criteria.add(Example.create(user).excludeZeroes());
[/code]