bookdaoimpl.java

达内网上购物系统

package org.whatisjava.dang.dao.hibernate;

import java.util.List;

import org.apache.log4j.Logger;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.whatisjava.dang.dao.BookDao;
import org.whatisjava.dang.util.DaoException;

public class BookDaoImpl implements BookDao {
	private static Logger logger = Logger.getLogger(BookDaoImpl.class);

	public List<?> findById(Integer id) throws DaoException {
		Session session = null;
		try {
			session = HbSessionFactory.getSession();
			Query query = session.createQuery("from Book b where b.id=?");
			query.setParameter(0, id);
			List<?> list = query.list();
			return list;
		} catch (HibernateException e) {
			logger.error("", e);
			throw new DaoException("", e);
		} finally {
			HbSessionFactory.closeSession();
		}
	}

	public List<?> findByCategoryId(Integer categoryId, int rowsPerPage,
			int page) throws DaoException {
		Session session = null;
		try {
			session = HbSessionFactory.getSession();
			Query query = session
					.createQuery("from Book b where b.categoryId=?");
			query.setParameter(0, categoryId);
			query.setMaxResults(rowsPerPage);
			query.setFirstResult(rowsPerPage * (page - 1));
			List<?> list = query.list();
			return list;
		} catch (HibernateException e) {
			logger.error("", e);
			throw new DaoException("", e);
		} finally {
			HbSessionFactory.closeSession();
		}
	}

	public int getTotalPagesByCategoryId(Integer categoryId, int rowsPerPage)
			throws DaoException {
		Session session = null;
		try {
			session = HbSessionFactory.getSession();
			Query query = session
					.createQuery("select count(*) from Book b where b.categoryId=?");
			query.setParameter(0, categoryId);

			List<?> list = query.list();
			int totalRows =((Long) list.get(0)).intValue();
			if (totalRows % rowsPerPage == 0) {
				return totalRows / rowsPerPage;
			} else {
				return totalRows / rowsPerPage + 1;
			}

		} catch (HibernateException e) {
			logger.error("", e);
			throw new DaoException("", e);
		} finally {
			HbSessionFactory.closeSession();
		}
	}

	public List<?> findByCategoryId(Integer categoryId) throws DaoException {
		Session session = null;
		try {
			session = HbSessionFactory.getSession();
			Query query = session
					.createQuery("from Book b where b.categoryId=?");
			query.setParameter(0, categoryId);
			List<?> list = query.list();
			return list;
		} catch (HibernateException e) {
			logger.error("", e);
			throw new DaoException("", e);
		} finally {
			HbSessionFactory.closeSession();
		}
	}

}