bookdao.java

模仿当当网基于struts+hierbernate与mysql的商务网站。

package org.whatisjava.dang.dao;

import java.util.List;

import org.hibernate.FlushMode;
import org.hibernate.Query;
import org.hibernate.Session;
import org.whatisjava.dang.domain.Book;

public class BookDao {
	/**
	 * 按上架时间 降序
	 */
	public final static int ADD_TIME_DESC = 0;
	/**
	 * 按上架时间 升序
	 */
	public final static int ADD_TIME_ASC = 1;
	/**
	 * 按出版时间 降序
	 */
	public final static int PUBLISH_TIME_DESC = 2;
	/**
	 * 按出版时间 升序
	 */
	public final static int PUBLISH_TIME_ASC = 3;
	/**
	 * 按价格 降序
	 */
	public final static int DANG_PRICE_DESC = 4;
	/**
	 * 按价格 升序
	 */
	public final static int DANG_PRICE_ASC = 5;

	private static final String[] ORDER_BY = {  "add_time desc" ,
			"add_time asc", "publish_time desc" ,"publish_time asc",
			"dang_price desc","dang_price asc"};

	public List<Book> findBookByPage(int cId, int orderBy, int numPerPage,
			int page) {
		if (orderBy < 0 || orderBy >= ORDER_BY.length) {
			orderBy = ADD_TIME_DESC;
		}
		Session session = HbSessionFactory.getSession();
		session.setFlushMode(FlushMode.NEVER);
		StringBuilder hql = new StringBuilder(
				"from Book b where b.category_id=? order by b.")
				.append(ORDER_BY[orderBy]);
		Query query = session.createQuery(hql.toString());
		query.setInteger(0, cId);
		query.setMaxResults(numPerPage);
		query.setFirstResult((page - 1) * numPerPage);
		List<Book> books = query.list();
		session.close();
		return books;
	}

	public int getBookTotalPageNum(int cId, int numPerPage) {
		Session session = HbSessionFactory.getSession();
		session.setFlushMode(FlushMode.NEVER);
		Query query = session
				.createQuery("select count(*) from Book b where b.category_id=?");
		query.setInteger(0, cId);
		int num = (Integer) query.list().get(0);
		session.close();
		if (num % numPerPage == 0) {
			return num / numPerPage;
		} else {
			return num / numPerPage + 1;
		}
	}

	public Book getById(int id) {
		Session session=HbSessionFactory.getSession();
		session.setFlushMode(FlushMode.NEVER);
		Book book=(Book)session.get(Book.class, id);
		session.close();
		return book;
	}
}