commentdao.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.Iterator;
import java.util.List;

import org.hibernate.FlushMode;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.whatisjava.dang.domain.Comment;
import org.whatisjava.dang.domain.Product;
import org.whatisjava.dang.domain.User;

public class CommentDao {

	public void save(Comment comment) {
		Session session=HbSessionFactory.getSession();
		Transaction tst=session.beginTransaction();
		if(session.load(User.class,comment.getUser().getId())!=null&&session.load(Product.class, comment.getProductId())!=null){
			session.save(comment);
			tst.commit();
		}
		session.close();
	}
	
	public void update(Comment comment) {
		Session session=HbSessionFactory.getSession();
		Transaction tst=session.beginTransaction();
		session.update(comment);
		tst.commit();
		session.close();
	}

	public Comment getById(Integer id, boolean withReply) {
		Session session=HbSessionFactory.getSession();
		session.setFlushMode(FlushMode.NEVER);
		Comment comment;
		if(withReply){
			Query query=session.createQuery("from Comment c left outer join fetch c.replies where c.id=?");
			query.setInteger(0, id);
			comment=(Comment) query.list().get(0);
		}else{
			comment=(Comment)session.get(Comment.class, id);
		}
		session.close();
		return comment;
	}

	public List<Comment> findByUser(User user, boolean withReply) {
		Session session=HbSessionFactory.getSession();
		session.setFlushMode(FlushMode.NEVER);
		List<Comment> list;
		if(withReply){
			Query query=session.createQuery("from Comment c left outer join fetch c.replies where c.user=? order by c.commentTime desc");
			query.setParameter(0,user);
			list=query.list();
			/*
			 * 过滤重复
			 * Hibernate 3.2.2可在hql中加入distinct解决
			 */
			Iterator<Comment> iterator=list.iterator();
			for(Comment comment=null;iterator.hasNext();){
				Comment next=iterator.next();
				if(next.equals(comment)){
					iterator.remove();
				}else{
					comment=next;
				}
			}
		}else{
			Query query=session.createQuery("from Comment c where c.user=? order by c.commentTime desc");
			query.setParameter(0,user);
			list=query.list();
		}
		session.close();
		return list;
	}

	public List<Comment> findByProduct(Product product, boolean withReply) {
		Session session=HbSessionFactory.getSession();
		session.setFlushMode(FlushMode.NEVER);
		List<Comment> list;
		if(withReply){
			Query query=session.createQuery("from Comment c left outer join fetch c.replies where c.productId=? order by c.commentTime desc");
			query.setInteger(0,product.getId());
			list=query.list();
			/*
			 * 过滤重复
			 * Hibernate 3.2.2可在hql中加入distinct解决
			 */
			Iterator<Comment> iterator=list.iterator();
			for(Comment comment=null;iterator.hasNext();){
				Comment next=iterator.next();
				if(next.equals(comment)){
					iterator.remove();
				}else{
					comment=next;
				}
			}
		}else{
			Query query=session.createQuery("from Comment c where c.productId=? order by c.commentTime desc");
			query.setInteger(0,product.getId());
			list=query.list();
		}
		session.close();
		return list;
	}

}