Hql（二）：通用BaseDao、原生SQL以及图映射

Hql学习②：通用BaseDao
一、BaseDAO
需求：
按名字分页查询对应书籍信息
准备：
(1) PageBean.java

package com.zking.eight.dao;

import java.util.Map;

import javax.servlet.http.HttpServletRequest;

/**
 * 分页工具类
 *
 */
public class PageBean {

	private int page = 1;// 页码

	private int rows = 3;// 页大小

	private int total = 0;// 总记录数

	private boolean pagination = true;// 是否分页
	// 获取前台向后台提交的所有参数
	private Map<String, String[]> parameterMap;
	// 获取上一次访问后台的url
	private String url;

	/**
	 * 初始化pagebean
	 * 
	 * @param req
	 */
	public void setRequest(HttpServletRequest req) {
		this.setPage(req.getParameter("page"));
		this.setRows(req.getParameter("rows"));
		// 只有jsp页面上填写pagination=false才是不分页
		this.setPagination(!"fasle".equals(req.getParameter("pagination")));
		this.setParameterMap(req.getParameterMap());
		this.setUrl(req.getRequestURL().toString());
	}

	public int getMaxPage() {
		return this.total % this.rows == 0 ? this.total / this.rows : this.total / this.rows + 1;
	}

	public int nextPage() {
		return this.page < this.getMaxPage() ? this.page + 1 : this.getMaxPage();
	}

	public int previousPage() {
		return this.page > 1 ? this.page - 1 : 1;
	}

	public PageBean() {
		super();
	}

	public int getPage() {
		return page;
	}

	public void setPage(int page) {
		this.page = page;
	}

	public void setPage(String page) {
		this.page = StringUtils.isBlank(page) ? this.page : Integer.valueOf(page);
	}

	public int getRows() {
		return rows;
	}

	public void setRows(int rows) {
		this.rows = rows;
	}

	public void setRows(String rows) {
		this.rows = StringUtils.isBlank(rows) ? this.rows : Integer.valueOf(rows);
	}

	public int getTotal() {
		return total;
	}

	public void setTotal(int total) {
		this.total = total;
	}

	public void setTotal(String total) {
		this.total = Integer.parseInt(total);
	}

	public boolean isPagination() {
		return pagination;
	}

	public void setPagination(boolean pagination) {
		this.pagination = pagination;
	}

	public Map<String, String[]> getParameterMap() {
		return parameterMap;
	}

	public void setParameterMap(Map<String, String[]> parameterMap) {
		this.parameterMap = parameterMap;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	/**
	 * 获得起始记录的下标
	 * 
	 * @return
	 */
	public int getStartIndex() {
		return (this.page - 1) * this.rows;
	}

	@Override
	public String toString() {
		return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination
				+ ", parameterMap=" + parameterMap + ", url=" + url + "]";
	}

}

(2) StringUtils.java

package com.zking.eight.dao;

public class StringUtils {
	// 私有的构造方法，保护此类不能在外部实例化
	private StringUtils() {
	}

	/**
	 * 如果字符串等于null或去空格后等于""，则返回true，否则返回false
	 * 
	 * @param s
	 * @return
	 */
	public static boolean isBlank(String s) {
		boolean b = false;
		if (null == s || s.trim().equals("")) {
			b = true;
		}
		return b;
	}
	
	/**
	 * 如果字符串不等于null或去空格后不等于""，则返回true，否则返回false
	 * 
	 * @param s
	 * @return
	 */
	public static boolean isNotBlank(String s) {
		return !isBlank(s);
	}

}

(3) Bookdao.java

package com.zking.eight.dao;

import java.io.Serializable;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

import com.zking.five.entity.Book;
import com.zking.two.util.SessionFactoryUtils;

public class BookDao extends BaseDao{
	public Book get(Book book) {
	 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()+"%");
		 }
		 //分页
		 if(pageBean != null && pageBean.isPagination()) {
			 query.setFirstResult(pageBean.getStartIndex());
			 query.setMaxResults(pageBean.getRows());
		 }
		 List list = query.list();
		 transaction.commit();
		 session.close();
		 return list;
	 }

	 public  List<Book> list2(Book book,PageBean pageBean){
		 Session session = SessionFactoryUtils.getSession();
		 Transaction transaction = session.beginTransaction();
		 String hql = "from Book where 1=1";
		 Map<String, Object> map = new HashMap<String, Object>();
		 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;
	 } 
	 
	 public  List<Object[]> list3(){
		 Session session = SessionFactoryUtils.getSession();
		 Transaction transaction = session.beginTransaction();
		 Map<String, Object> map = new HashMap<String, Object>();
		 String hql = "select b.bookName,o.OrderNo from Book b, Order o where 1=1";
		 List list = session.createQuery(hql).list();
//		 String sql = "select b.book_name,o.order_no form t_hibernate_book b,t_hibernate_order o where 1 = 1";
//		 List list = session.createSQLQuery(sql).list();
		 transaction.commit();
		 session.close();
		 return list;
	 } 
}

(4) BaseDao

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;

/**
 * 作用：
 * 	1、将赋值的操作交给basedao
 * 	2、分页
 * 		a：查询出符合条件的总记录数
 * 		b：查询符合条件的某一页记录
 * @author Administrator
 *
 */

public class BaseDao {
	/**
	 * 赋值的操作
	 * @param query  预定义对象
	 * @param map   前台穿过来的参数
	 */
	//定义私有  可以减少操作（便于直接调用一个方法就能调用所有的方法  进行所有操作）
	private void setParameter(Query query,Map<String, Object> map) {
//		 query.setParameter("bookName", "%"+book.getBookName()+"%");
		//如果前台没有传参数
		if(map == null && map.size() == 0) {
			//则返回  
			return ;
		}
		//定义一个对象  用来接收前台传过来的值
		Object value = null;
		//将前台穿过来的值用for循环遍历
		for (Map.Entry<String, Object> entry : map.entrySet()) {
			//放入map集合中
			value = entry.getValue();
			//①  假如穿过来的值为Collection集合
			if(value instanceof Collection) {
				query.setParameterList(entry.getKey(), (Collection)value);
			}
			//②  假如穿过来的值为Object[]集合
			else if(value instanceof Object[]) {
				query.setParameterList(entry.getKey(), (Object[])value);
			}
			//③  普通情况
			else {
				query.setParameter(entry.getKey(), value); 
			}
		}
	}
	
	/**
	 *  aql = select * from t_hibernate_book where book_name like '%霸道%'
	 *  countSql = selct count(*)  from (select * from t_hibernate_book where book_name like '%霸道%')
	 *  pageSql =  sql + " limit ?,?"  hibernate中可省略
	 *  
	 *  
	 *  hql = from Book where bookName like '%霸道%'
	 *  hql = select bookName,price from Book where bookName like '%霸道%'
	 *  
	 *  思路：
	 *  	截取from后的sql语句，前面拼接select count(*)
	 *  
	 */
	
	/** 
	 * 分页一：
	 *  查询出符合条件的总记录数
	 * @param hql
	 * @return
	 */
	public String getCountHql(String hql) {
		int index = hql.toUpperCase().indexOf("FROM");
		return "select count(*) "+hql.substring(index);
	}
	/**
	 * 分页二：
	 * 	查询符合条件的某一页记录
	 * @param session
	 * @param hql
	 * @param pageBean
	 * @param map
	 * @return
	 */
	public List executeQuery(Session session,String hql,PageBean pageBean,Map<String, Object> map) {
		//如果有分页操作
		if(pageBean != null && pageBean.isPagination()) {
			 //select count(*) from Book wehre bookName like '%霸道%'
			 String countHql = getCountHql(hql);
			 Query countQuery = session.createQuery(countHql);
			 this.setParameter(countQuery, map);
			 //pageBean设置总记录数，最后用于分页
			 String total = countQuery.getSingleResult().toString();
			 pageBean.setTotal(total);
			 
			 //查询展示的数据
			 Query pagequery = session.createQuery(hql);
			 this.setParameter(pagequery, map);
			 pagequery.setFirstResult(pageBean.getStartIndex());
			 pagequery.setMaxResults(pageBean.getRows());
			 
			 return pagequery.list();
		 }//不分页
		 else {
			 Query query = session.createQuery(hql);
			 this.setParameter(query, map);
			 return query.list();
		 }
	}
	

}

二、原生sql
hql实现不了的功能，可以考虑使用原生sql
1、多表（5+）联查
2、关系复杂，未配置映射文件中关系

三、图映射