Spring用回调HibernateCallBack方法

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Spring用回调HibernateCallBack方法实现持久层一些功能,当这些功能不能满足需求时,我们也可以自已来重写HibernateCallBack,例:
public class UsersDAO extends HibernateDaoSupport {
   ......
public List getUsers() {
  return getHibernateTemplate().executeFind(new HibernateCallback() {
   public Object doInHibernate(Session s) throws HibernateException,
     SQLException {
    Query query = s.createQuery("From Users AS user ORDER BY user.username DESC");
    List list = query.list();
    return list;
   }
  });
}
  ......
}
但是这样的代码很难让人理解,可以将其打包
package com.notepad.comm;
import java.sql.SQLException;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.springframework.orm.hibernate3.HibernateCallback;
public class HQLCallBackUtil implements HibernateCallback {
private String hql;

public HQLCallBackUtil(){
 
}

public HQLCallBackUtil(String hql){
  this.hql=hql;
}
public String getHql() {
  return hql;
}
public void setHql(String hql) {
  this.hql = hql;
}
public Object doInHibernate(Session s) throws HibernateException,
   SQLException {
  if (hql == null || hql.equals("")) {
   throw new HibernateException("Can't execute NULL hql!");
  }
  return s.createQuery(hql).list();
}
}
然后可以通过如下代码进行调用
public class UsersDAO extends HibernateDaoSupport {
   ......
public List getUsers() {
     HQLCallBackUtil callBack=new HQLCallBackUtil();
     callBack.setHql("From Users AS user ORDER BY user.username DESC");
     return this.getHibernateTemplate().executeFind(callBack);
}
  ......
}
这样是不是感觉简单很多呢!