Hibernate 4: EL表达式上的LazyInitializationException

Question

我有以下实体继承，让我们从根开始(它只是一个带有自动增量整数ID的表)：

@Entity
@Table(name = "Contacts")
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = "discriminator", discriminatorType = DiscriminatorType.STRING)
public abstract class Contact implements Serializable
{
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column
    protected Integer id;

    ...
}

OrganizationalUnit只是一个名称加上继承的ID：

@Entity
@Table(name = "OrganizationalUnits")
public abstract class OrganizationalUnit extends Contact
{
    @Column
    protected String name;

    ...
}

Organization只是一个空实体(用于引用)：

@Entity
@Table(name = "Organizations")
public abstract class Organization extends OrganizationalUnit
{
    ...
}

最后但同样重要的是：

@Entity
@Table(name = "Companies")
@DiscriminatorValue(value = "company")
public class Company extends Organization
{
    @Basic(optional = false)
    @Column(name = "dnd_type")
    private String dndType;

    ...
}

这使得公司有3个列/字段: ID、名称和dnd类型。

每个公司都是从系统中的文档实体中引用的(每个文档都有一个拥有公司)：

@Entity
@Table(name = "Documents")
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = "discriminator", discriminatorType = DiscriminatorType.STRING)
public abstract class Document implements Serializable
{
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column
    protected Integer id;

    @Basic(optional = false)
    @Column(name = "file_name")
    protected String fileName;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "company_id", referencedColumnName = "id")
    protected Company company;

    ...
}

注意公司关系上的@ManyToOne(fetch = FetchType.LAZY, optional = false)。这里必须不要有惰性，这里使用急切的提取类型解决了我在这里讨论的问题--(但我想让它与惰性一起工作，也是因为我使用代码生成器来重新生成实体类.它必须起作用！)

对于JSF页面中的每个文档，我都引用了Company的dndType，比如：

<ui:include src="/subviews/repo-filename-dnd-panel.xhtml">
  <ui:param name="document" value="#{doc}" />
  <ui:param name="documentFileName" value="#{doc.fileName}" />
  <ui:param name="documentCompanyName" value="#{doc.company.name}" />
  <ui:param name="documentCompanyDndSuffix" value="#{doc.company.dndType}" /> <!-- EXCEPTION HERE -->
</ui:include>

这些只是传递到一个子视图/subviews/repo-filename-dnd-panel.xhtml，在那里，我只是引用params，例如documentCompanyDndSuffix，来构造一些HTML。

我现在得到的#{doc.company.dndType}是：

13:53:56,043 SEVERE [org.richfaces.log.Context] (http--127.0.0.1-8080-3) /subviews/repo-filename-dnd-panel.xhtml @14,63 type="doc-#{documentCompanyDndSuffix}": /pq-edit.xhtml @139,94 value="#{doc.company.dndType}": org.hibernate.LazyInitializationException: could not initialize proxy - no Session: javax.el.ELException: /subviews/repo-filename-dnd-panel.xhtml @14,63 type="doc-#{documentCompanyDndSuffix}": /pq-edit.xhtml @139,94 value="#{doc.company.dndType}": org.hibernate.LazyInitializationException: could not initialize proxy - no Session
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at org.richfaces.component.UIDragSource.getType(UIDragSource.java:95) [richfaces-components-ui-4.1.0.Final.jar:]
    at org.richfaces.renderkit.DragSourceRenderer.getOptions(DragSourceRenderer.java:55) [richfaces-components-ui-4.1.0.Final.jar:]
    at org.richfaces.renderkit.DnDRenderBase.buildClientScript(DnDRenderBase.java:66) [richfaces-components-ui-4.1.0.Final.jar:]
    at org.richfaces.renderkit.DnDRenderBase.buildAndStoreScript(DnDRenderBase.java:43) [richfaces-components-ui-4.1.0.Final.jar:]
    at org.richfaces.renderkit.DnDRenderBase.doEncodeEnd(DnDRenderBase.java:74) [richfaces-components-ui-4.1.0.Final.jar:]
    at org.richfaces.renderkit.RendererBase.encodeEnd(RendererBase.java:175) [richfaces-components-ui-4.1.0.Final.jar:]
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1763) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at org.richfaces.renderkit.RendererBase.renderChildren(RendererBase.java:276) [richfaces-components-ui-4.1.0.Final.jar:]
    at org.richfaces.renderkit.html.AjaxOutputPanelRenderer.encodeChildren(AjaxOutputPanelRenderer.java:57) [richfaces-components-ui-4.1.0.Final.jar:]
.
. lots of RichFaces and JSF stuff
.
    at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:626) [jbossweb-7.0.7.Final.jar:]
    at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:2033) [jbossweb-7.0.7.Final.jar:]
    at java.lang.Thread.run(Unknown Source) [:1.7.0_02]
Caused by: org.hibernate.LazyInitializationException: could not initialize proxy - no Session
    at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:149) [hibernate-core-4.0.0.Final.jar:4.0.0.Final]
    at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:195) [hibernate-core-4.0.0.Final.jar:4.0.0.Final]
    at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185) [hibernate-core-4.0.0.Final.jar:4.0.0.Final]
    at de.poyry.pqgenerator.model.Company_$$_javassist_22.getDndType(Company_$$_javassist_22.java) [classes:]
    at sun.reflect.GeneratedMethodAccessor457.invoke(Unknown Source) [:1.7.0_02]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [:1.7.0_02]
    at java.lang.reflect.Method.invoke(Unknown Source) [:1.7.0_02]
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:302) [jboss-el-api_2.2_spec-1.0.0.Final.jar:1.0.0.Final]
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at org.apache.el.parser.AstValue.getValue(AstValue.java:169) [jbossweb-7.0.7.Final.jar:]
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189) [jbossweb-7.0.7.Final.jar:]
    at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50) [weld-core-1.1.4.Final.jar:2011-11-22 20:01]
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:67) [jbossweb-7.0.7.Final.jar:]
    at org.apache.el.parser.AstDeferredExpression.getValue(AstDeferredExpression.java:44) [jbossweb-7.0.7.Final.jar:]
    at org.apache.el.parser.AstCompositeExpression.getValue(AstCompositeExpression.java:50) [jbossweb-7.0.7.Final.jar:]
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189) [jbossweb-7.0.7.Final.jar:]
    at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50) [weld-core-1.1.4.Final.jar:2011-11-22 20:01]
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    ... 72 more

我不知道为什么这里有一个LazyInitializationException，因为Company实体并不暗示懒得冬眠4，而且以前对#{doc.company.name}的调用也很好。

更新：

我最近在GlassFish 3.1.2上测试了这一点，一切都很好。因此，我开始相信这是某种类型的JBoss (7)，或者更确切地说( JBoss )是事务管理问题/策略不匹配。

我的假设是，公司名称在某些事务中被访问和取消代理，在实体管理器关闭后，访问了尚未取消代理的dndType (而name已被取消代理)。在我看来，这就像是EJB事务处理问题(在这里，我仍然有缺陷).

我很快就会在这里添加更多的信息。

Answer 1

问题是，该公司并没有在声明中提及--那么简单。在类似的情况下，我只是偶尔感到幸运，因为一个事务仍然是活跃的，所以这一次似乎失败了，但实际上其他事务也是如此。

我没有意识到，当从JSF页面访问时，从DB获取文档列表的方法已经运行，事务已经消失。

Answer 2

您应该尝试如下: fetch = FetchType.EAGER它解决了我的问题。