java - 当我试图从数据库中获取数据时 hibernate "No session or session was closed"

Question

我正在尝试编写一个库存管理系统。但现在我有几个问题。请帮我解决这些问题。

我有 2 个实体。 Item 和 ItemPrice。 Item 有一个或多个 ItemPrice

当我尝试保存 Item 对象时，它工作正常；但是当我尝试从数据库中检索详细信息时，它给出了以下 Exception 堆栈跟踪。

org.hibernate.HibernateException: Found shared references to a collection: com.pos.entities.ItemGroup.items
Hibernate: select itemmodel0_.id as id9_, itemmodel0_.item_model as item2_9_, itemmodel0_.status as status9_ from smartpos.item_model itemmodel0_ where (itemmodel0_.status=? )
Hibernate: select itemsize0_.id as id3_, itemsize0_.item_size as item2_3_, itemsize0_.status as status3_ from smartpos.item_size itemsize0_ where (itemsize0_.status=? )
    at org.hibernate.engine.Collections.processReachableCollection(Collections.java:163)
    at org.hibernate.event.def.FlushVisitor.processCollection(FlushVisitor.java:37)
    at org.hibernate.event.def.AbstractVisitor.processValue(AbstractVisitor.java:101)
    at org.hibernate.event.def.AbstractVisitor.processValue(AbstractVisitor.java:61)
    at org.hibernate.event.def.AbstractVisitor.processEntityPropertyValues(AbstractVisitor.java:55)
    at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:138)
    at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:196)
    at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:76)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:26)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
    at com.pos.dao.ItemDaoImpl.getItem(ItemDaoImpl.java:761)
    at com.pos.manager.ItemManager.getItem(ItemManager.java:296)
    at com.pos.ui.ItemDefinitionForm$RefreshTask.doInBackground(ItemDefinitionForm.java:464)
    at com.pos.ui.ItemDefinitionForm$RefreshTask.doInBackground(ItemDefinitionForm.java:458)
    at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at javax.swing.SwingWorker.run(SwingWorker.java:316)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)
Nov 7, 2012 12:03:42 PM org.hibernate.LazyInitializationException 
SEVERE: failed to lazily initialize a collection of role: com.pos.entities.Item.itemPrices, no session or session was closed
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.pos.entities.Item.itemPrices, no session or session was closed
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:358)
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:350)
    at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:97)
    at org.hibernate.collection.PersistentSet.size(PersistentSet.java:139)
    at com.pos.ui.ItemDefinitionForm$RefreshTask.doInBackground(ItemDefinitionForm.java:520)
    at com.pos.ui.ItemDefinitionForm$RefreshTask.doInBackground(ItemDefinitionForm.java:458)
    at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at javax.swing.SwingWorker.run(SwingWorker.java:316)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.pos.entities.Item.itemPrices, no session or session was closed
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:358)
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:350)
    at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:97)
    at org.hibernate.collection.PersistentSet.size(PersistentSet.java:139)
    at com.pos.ui.ItemDefinitionForm$RefreshTask.doInBackground(ItemDefinitionForm.java:520)
    at com.pos.ui.ItemDefinitionForm$RefreshTask.doInBackground(ItemDefinitionForm.java:458)
    at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at javax.swing.SwingWorker.run(SwingWorker.java:316)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

This is entity class files.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Nov 3, 2012 10:36:51 PM by Hibernate Tools 3.2.1.GA -->
<hibernate-mapping>
<class catalog="smartpos" name="com.pos.entities.ItemPrice" table="item_price" lazy="false">
<id name="id" type="java.lang.Integer">
  <column name="id"/>
  <generator class="identity"/>
</id>
<many-to-one class="com.pos.entities.Item" fetch="select" name="item">
  <column name="item_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.PriceList" fetch="select" name="priceList">
  <column name="price_list_id" not-null="true"/>
</many-to-one>
<property name="price" type="float">
  <column name="price" not-null="true" precision="12" scale="0"/>
</property>

项目实体

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"     "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Nov 3, 2012 10:36:51 PM by Hibernate Tools 3.2.1.GA -->
<hibernate-mapping>
<class catalog="smartpos" lazy="false" name="com.pos.entities.Item" table="item">
<id name="id" type="java.lang.Integer">
  <column name="id"/>
  <generator class="identity"/>
</id>
<many-to-one class="com.pos.entities.ItemColor" fetch="select" name="itemColor">
  <column name="item_color_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.ItemModel" fetch="select" name="itemModel">
  <column name="item_model_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.ItemGrade" fetch="select" name="itemGrade">
  <column name="item_grade_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.BusinessPartner" fetch="select" name="businessPartner">
  <column name="supplier_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.ItemSize" fetch="select" name="itemSize">
  <column name="item_size_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.Login" fetch="select" name="login">
  <column name="login_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.ItemGroup" fetch="select" name="itemGroup">
  <column name="item_group_id" not-null="true"/>
</many-to-one>
<many-to-one class="com.pos.entities.ItemBrand" fetch="select" name="itemBrand">
  <column name="item_brand_id" not-null="true"/>
</many-to-one>
<property name="itemCode" type="string">
  <column length="50" name="item_code" not-null="true" unique="true"/>
</property>
<property name="itemName" type="string">
  <column length="200" name="item_name" not-null="true"/>
</property>
<property name="shortName" type="string">
  <column length="100" name="short_name" not-null="true"/>
</property>
<property name="barcode" type="string">
  <column length="50" name="barcode" not-null="true"/>
</property>
<property name="warrentyItem" type="byte">
  <column name="warrenty_item" not-null="true"/>
</property>
<property name="taxableItem" type="byte">
  <column name="taxable_item" not-null="true"/>
</property>
<property name="status" type="byte">
  <column name="status" not-null="true"/>
</property>
<property name="createdDate" type="timestamp">
  <column length="19" name="created_date" not-null="true"/>
</property>
<property name="batchSerial" type="byte">
  <column name="batch_serial" not-null="true"/>
</property>
<property name="warrentyPeriod" type="int">
  <column name="warrenty_period" not-null="true"/>
</property>
<set inverse="true" name="itemPrices" cascade="save-update">
  <key>
    <column name="item_id" not-null="true"/>
  </key>
  <one-to-many class="com.pos.entities.ItemPrice"/>
</set>

GUI 编码

headers = new SupportedMethod().getTableHeaderValues(tblItemPrice);
System.out.println("sdff" + item.getItemPrices().size());
itemPriceSet = item.getItemPrices();
Iterator it = itemPriceSet.iterator();

while (it.hasNext()) {
    ItemPrice ip = (ItemPrice) it.next();
    Vector<Object> oneRow = new Vector<Object>();

    oneRow.add(ip.getId());
    oneRow.add(ip.getPriceList().getPriceListName());
    oneRow.add(Float.toString(ip.getPrice()));

    tableData.add(oneRow);
}
tblItemPrice.setModel(new DefaultTableModel(tableData, headers));

cascade 没问题，我已经设置了lazy=false，但是它抛出Exception。 请任何人帮助我。

Answer 1

stacktrace 中的这些行表明您的 Item.itemPrices 集使用延迟初始化:

collection of role: com.pos.entities.Item.itemPrices, no session or session was closed at
org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:358)
...

所以请将 lazy="false"添加到 itemPrices 集合中:

<set inverse="true" name="itemPrices" lazy="false" fetch="select" cascade="save-update">
  <key>
    <column name="item_id" not-null="true"/>
  </key>
  <one-to-many class="com.pos.entities.ItemPrice"/>
</set>