求助hibernate ：failed to lazily initialize a collect

[sunboyqq23]

这是Bill.hbm.xml:

  <class name="entity.Bill" table="Bill">
      <id name="id" column="oid">
          <generator class="increment" />
      </id>
      <property name="tableNum" column="table_num" />
      <property name="consumption" column="consumption" />
      <property name="isFinished" column="is_finished" />
      <property name="createDate" column="create_date" />

      <set name="itemSet" cascade="all" lazy="false">
          <key column="Bill_id" />
          <one-to-many class="entity.Item" />
      </set>
  </class>

测试代码：

Dish dish1 = DishDAO.findDishByName("apple");
        Bill bill = BillDAO.findBill("B");
        Item item = ItemDAO.createItem(new Item(1,dish1));
        bill.getItemSet().add(item);

BillDAO.findBill()

public static Bill findBill(String tableNum) throws Exception {

        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction tx = session.beginTransaction();
        Bill bill;

        Query query = session.createQuery("from Bill bill where bill.tableNum=:tableNum and bill.isFinished=false");
        query.setParameter("tableNum", tableNum);
        List list = query.list();
        Iterator iter = list.iterator();

        if(iter.hasNext()) {
            bill = (Bill) iter.next();
        }else {
            tx.commit();
            session.close();
            throw new Exception("bill not found");
        }

        tx.commit();
        session.close();

        return bill;
        
    }

我在网上查到是hibernate懒加载的问题，其中一种解决方法是把lazy设置成false，我这么做了，但是为什么还会发生相同的错误呢，我是在netbeans下运行

[hoseli007]

表结构是否设计正确？

[穆大叔]

使用spring提供的opensessioninviewfilter过滤器，在web.xml加上

<filter>
	        <filter-name>OpenSessionInViewFilter</filter-name>
	        <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
	</filter>
	<filter-mapping>
	        <filter-name>OpenSessionInViewFilter</filter-name>
	        <url-pattern>/*</url-pattern>
	</filter-mapping>