DaoImpl中实现查询分页-使用HibernateCallback来做更加方便

/**
 *
 */
package com.wolfgang.dao;

import java.sql.SQLException;
import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.wolfgang.VO.PageVO;

/**
 * @author Administrator
 *
 */
public class BaseDaoImp extends HibernateDaoSupport implements IBaseDao {

    public Object get(Integer id) {
        return getHibernateTemplate().get(Object.class, id);
    }

    /*
     * (non-Javadoc)
     *
     * @see com.wolfgang.dao.IBaseDao#save(java.lang.Object)
     */

    public void save(Object obj) {
        getHibernateTemplate().save(obj);
    }

    /*
     * (non-Javadoc)
     *
     * @see com.wolfgang.dao.IBaseDao#update(java.lang.Object)
     */

    public void update(Object obj) {
        getHibernateTemplate().update(obj);
    }

    /*
     * (non-Javadoc)
     *
     * @see com.wolfgang.dao.IBaseDao#delete(java.lang.Object)
     */
    public void delete(Object obj) {
        getHibernateTemplate().delete(obj);
    }

    /*
     * (non-Javadoc)
     *
     * @see com.wolfgang.dao.IBaseDao#findById(int)
     */
    public <T> T findById(Class<T> className, int id) {
        return (T) getHibernateTemplate().get(className, id);
    }

    /*
     * (non-Javadoc)
     *
     * @see com.wolfgang.dao.IBaseDao#getAll(java.lang.Class)
     */
    public <T> List<T> getAll(Class<T> className) {
        return getHibernateTemplate().loadAll(className);

    }

    /*
     * (non-Javadoc)
     *
     * @see com.wolfgang.dao.IBaseDao#findPage(java.lang.String, int, int,
     * java.lang.Object[])
     */
    public PageVO findPage(final String hql, int offset, int pageSize,
            final Object... params) {
        final String totalHql = getTotalHql(hql);
        Long total = (Long) getHibernateTemplate().execute(
                new HibernateCallback() {

                    public Object doInHibernate(Session session)
                            throws HibernateException, SQLException {
                        Query query = session.createQuery(totalHql);
                        return query.uniqueResult();
                    }
                });

        List data = (List) getHibernateTemplate().execute(
                new HibernateCallback() {
                    public Object doInHibernate(Session session)
                            throws HibernateException, SQLException {

                        Query query = session.createQuery(hql);
                        if (params != null) {
                            for (int i = 0; i < params.length; i++) {
                                query.setParameter(i, params[i]);
                            }
                        }

                        return query.list();
                    }
                });

        PageVO pageVO = new PageVO();
        pageVO.setTotal(total);
        pageVO.setData(data);
        return pageVO;
    }

    private String getTotalHql(String hql) {
        int index = hql.indexOf(hql);
        if (index == -1) {
            return null;
        } else {
            return "select count(*)" + hql.substring(index);
        }

    }

}