BaseDAO需求

• 作用：

• 1、將賦值的操作交給basedao
• 2、分頁 a、查詢出符合條件的總記錄數 b、查詢符合條件的某一頁記錄

package com.zking.eight.dao;

import java.util.Collection;
import java.util.List;
import java.util.Map;

import org.hibernate.Session;
import org.hibernate.query.Query;

import com.zking.eight.util.PageBean;

/**
 * 作用：
 * 1、將賦值的操作交給basedao
 * 2、分頁
 * 	a、查詢出符合條件的總記錄數
 * 	b、查詢符合條件的某一頁記錄
 * @author Administrator
 *
 */
public class BaseDao {

	/**
	 * 賦值的操作
	 * @param query 預定義物件
	 * @param map	前臺傳遞過來的引數
	 */
	public void setParameter(Query query,Map<String, Object> map) {
//		query.setParameter("bookname", "%"+book.getBookname()+"%");
		if(map == null || map.size()==0) {
			return;
		}
		Object values = null;
		for (Map.Entry<String, Object> entry : map.entrySet()) {
			values = entry.getValue();
			if(values instanceof Collection) {
				query.setParameterList(entry.getKey(), (Collection) values);
			}
			else if(values instanceof Object[]) {
				query.setParameterList(entry.getKey(), (Object[]) values);
			}
			else {
				query.setParameter(entry.getKey(), values);
			}
		}
	}
	
	
	/**
	 * 思路：
	 * 	擷取from後的sql語句，前面拼接select count(*)
	 * 
	 * 轉成大寫
	 */
	
	//查詢出符合條件的總記錄數
	public String getCountHql(String hql) {
		int index = hql.toUpperCase().indexOf("FROM");		
		return "select count(*)"+hql.substring(index);		
	}
	
	
	public List executeQuery(Session session, String hql,PageBean pageBean,Map<String, Object> map) {
		if( pageBean != null && pageBean.isPagination()) {
			String countHql = getCountHql(hql);			
			Query countQuery = session.createQuery(countHql);
			this.setParameter(countQuery, map);		
			//pagebean設定總記錄數，最後用於分頁
			pageBean.setTotal(countQuery.getSingleResult().toString());
			//查詢展示的資料
			Query pageQuery = session.createQuery(hql);
			this.setParameter(pageQuery, map);
			pageQuery.setFetchSize(pageBean.getStartIndex());
			pageQuery.setMaxResults(pageBean.getRows());
		
			return pageQuery.list();	
		}
		else {
			Query query = session.createQuery(hql);
			this.setParameter(query, map);
			return query.list();	
		}
			
	}
	
	
}

 

dao方法： 沒有BaseDao方法：

public List<Book> list1(Book book,PageBean pageBean){
		
		Session session = SessionFactoryUtils.getSession();
		Transaction transaction = session.beginTransaction();
		String hql = "from Book where 1=1";
		if(StringUtils.isNotBlank(book.getBookname())) {
			hql += " and bookname like :bookname ";			
		}
		Query query = session.createQuery(hql);
		if(StringUtils.isNotBlank(book.getBookname())) {
			query.setParameter("bookname", "%"+book.getBookname()+"%");
		}
		if( pageBean != null && pageBean.isPagination()) {
			query.setFirstResult(pageBean.getStartIndex());
			query.setMaxResults(pageBean.getRows());
		}
		List list = query.list();
		transaction.commit();
		session.close();		
		return list;
		
	}
 

繼承BaseDao方法：

	public List<Book> list2(Book book,PageBean pageBean){
		
		Session session = SessionFactoryUtils.getSession();
		Transaction transaction = session.beginTransaction();		
		Map<String, Object> map = new HashMap<>();
		String hql = "from Book where 1=1";
		if(StringUtils.isNotBlank(book.getBookname())) {
			hql += " and bookname like :bookname ";	
			map.put("bookname", book.getBookname());
		}		
		List list = super.executeQuery(session, hql, pageBean, map);		
		transaction.commit();
		session.close();		
		return list;
		
	}
 

原生態SQL

hql實現不了的功能，可以考慮使用原生sql，例如： 1、多表（5+）聯查 2、未配置對映檔案中關係

	public List<Object[]> list3(Book book,PageBean pageBean){
		
		Session session = SessionFactoryUtils.getSession();
		Transaction transaction = session.beginTransaction();		
		Map<String, Object> map = new HashMap<>();
//		String hql = " select b.bookname,o.orderId from Book b,Order o where 1=1";				
//		 List list = session.createQuery(hql).list();
		//原生態SQL
		 String sql = " select b.book_name,o.order_id from t_hibernate_book b,t_hibernate_order o where 1=1";
		 List list = session.createSQLQuery(sql).list();
		transaction.commit();
		session.close();		
		return list;
		
	}

檢視對映

hibernate支援檢視對映

	public List<Object[]> list3(Book book,PageBean pageBean){
		
		Session session = SessionFactoryUtils.getSession();
		Transaction transaction = session.beginTransaction();		
		Map<String, Object> map = new HashMap<>();
		//檢視對映
		 String sql = " select * from book_order";
		 List list = session.createSQLQuery(sql).list();
		transaction.commit();
		session.close();		
		return list;
		
	}