Question

我正在为GlassFish 4创建一个JSF + JPA项目。有几次我在此时遇到异常：

List<User> users = connection.getUserList();

for (User u : users) { //exception

...

    public List<User> getUserList() {

    EntityManager em = Persistence.createEntityManagerFactory("project").createEntityManager();
    List<User> users = em.createQuery("SELECT c FROM User c", User.class).getResultList();
    em.close();
    return users;
}

堆栈跟踪：

javax.faces.el.EvaluationException: java.lang.ClassCastException: de.sep.ateam.sap.norris.model.User cannot be cast to de.sep.ateam.sap.norris.model.User
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
    at javax.faces.component.UICommand.broadcast(UICommand.java:315)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
    at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ClassCastException: de.sep.ateam.sap.norris.model.User cannot be cast to de.sep.ateam.sap.norris.model.User
    at de.sep.ateam.sap.norris.controller.beans.LoginBean.doLogin(LoginBean.java:50)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at javax.el.ELUtil.invokeMethod(ELUtil.java:326)
    at javax.el.BeanELResolver.invoke(BeanELResolver.java:536)
    at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:256)
    at com.sun.el.parser.AstValue.invoke(AstValue.java:269)
    at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
    at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
    at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
    ... 35 more

Answer 1

如果您确定在应用程序服务器中没有加载同一类的多个版本，则可能会尝试重置服务器缓存。

请按照以下步骤操作：

取消部署应用程序;
停止应用程序服务器;
删除应用程序服务器的osgi缓存文件夹。即如果你是使用glassfish，它是文件夹： E：\与GlassFish 3.1.2.2 \的glassfish \域\ domain1的\ OSGi的高速缓存
重启服务器;
部署应用程序。

Answer 2

我有同样的问题，我终于找到了一个关于java.net的解决方法：

将org.eclipse.persistence jar files的所有glassfish4/glassfish/modules复制到WEB-INF/lib。然后进入glassfish-web.xml，并将class-delegate设置为false。

为我工作！

Answer 3

我遇到了类似的问题，因为我正在序列化类，并且在更新类并重新启动应用程序而不重新启动容器后，序列化版本无法反序列化。

Answer 4

通常，当在不同的类加载器中存在多个相同jar的实例时，会发生这种情况。大多数应用服务器都有一个全局类加载器和一个特定于Web应用程序的类加载器（有些还有其他像contrib等）。如果食物链中较高的类加载器已经定义了该类，并且它被较低级别的类加载器重新定义，则会发生这种情况（即使它的定义是相同的，不同类加载器中的相同类被认为是不同的相同）。罐子如何/何时加载的顺序不能保证，这可以解释为什么你有时会看到错误，有时却没有。简而言之，请确保您尚未在Web服务器可见的服务器中的其他位置部署包含此类的jar。

java.lang.ClassCastException：com.example.Entity无法强制转换为com.example.Entity

4 个答案: