jdbc 和 hibernate框架 分页的思路

• • 分页： jdbc:
• –>
• executeQuery(String sql,PageBean pagebean,Class clz)
• sql:select from t_hibernate_book where book_name like ‘%?%’

•  select * from t_hibernate_book where book_name like '%西%'
  

•  countSql = select count(*) from (sql) t;
  

• 分页： 1、sql–>countSql–>total–>pageBean

•  2、sql-->pageSql-->result 
  

•  3、处理结果集
  

• hql:

•  0、select * from Book where bookName like '%:bookName%' select count(*)
  

•     sql from From frOm 
  

•  1、hql-->countHql-->total-->pageBean
  

•  2、sql-->pageSql-->result（hibernate调用内置接口自动生成分页语句，查询结果） 3、不需要
  

• @author 海峰几

*/

public class BaseDao {
	private void setParameter(Query query,Map<String, Object> map) {
		if(map ==null || map.size()==0) {
			return;
		}
		Object value = null;
//		给query赋值
		for(Map.Entry<String, Object> entry :map.entrySet()) {
			value = entry.getValue();
			if(value instanceof Collection) {
				query.setParameterList(entry.getKey(), (Collection) value);
			} else if(value instanceof Object[]) {
				query.setParameterList(entry.getKey(), (Object[]) value);
			} else {
				query.setParameter(entry.getKey(), value);
			}
		}
	}
	
	private String getCountHql(String hql) {
		int index = hql.toUpperCase().indexOf("FROM");
		return "select count(*)" +hql.substring(index);
	}
	
	public List executeQuery(String hql,PageBean pageBean,Map<String, Object> map,Session session){
		if(pageBean != null && pageBean.isPagination()) {
			String countHql = getCountHql(hql);
			Query countQuery = session.createQuery(countHql);
			this.setParameter(countQuery, map);
			String total = countQuery.getSingleResult().toString();
			pageBean.setTotal(total);
			
			Query pageQuery = session.createQuery(hql);
			this.setParameter(pageQuery, map);
			pageQuery.setFirstResult(pageBean.getStartIndex());
			pageQuery.setMaxResults(pageBean.getRows());
			
			return pageQuery.list();
		}else {
			Query query = session.createQuery(hql);
			this.setParameter(query, map);
			return query.list();
		}
	}