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在搜索的日子里，我找不到任何有用的东西。也许我只是没有找对地方。

这里的想法 - 非常简单：我想通过 J2EE 中的内置 RMI 将一个对象从一个 EJB 传递到另一个。

据我所知，这是可能的，但我发现人们说的唯一真实的事情是使对象可序列化，所以我有（实际上我序列化了它的废话），但仍然没有骰子。所以这是一个测试用例，当关键代码未注释时，这会导致NullPointerException 。

我应该提到，在尝试完成这项工作时，我遇到了许多我无法克服的错误。这只是我在这个简单示例中得到的错误。我希望有人可以帮助我解决这个特定的问题，我可以对其进行调整。

因此，在 NetBeans 中工作时，Glassfish 服务器已完全更新，我有一个企业应用程序，其中包括另外两个项目：一个EJB 项目和一个Web 项目。

有以下共享接口：

ejbModule.interfaces.ABeanInterface

package ejbModule.interfaces;

import javax.ejb.Remote;

@Remote
public interface ABeanInterface {

    public SrzedObjInterface getObject();
    public String getString(); // To show that a simple String object can be passed

}

ejbModule.interfaces.SrzedObjInterface

package ejbModule.interfaces;

import java.io.Serializable;

public interface SrzedObjInterface extends Serializable {

    public String getTheString();

}

EJB 项目具有以下类：

ejbModule.ejb.ABean：

package ejbModule.ejb;

import ejbModule.interfaces.ABeanInterface;
import ejbModule.obj.SrzedObj;
import ejbModule.interfaces.SrzedObjInterface;
import javax.ejb.Stateless;

@Stateless
public class ABean implements ABeanInterface {

    @Override
    public SrzedObjInterface getObject() {
        return new SrzedObj();
    }

    @Override
    public String getString() {
        return "This is not the String I want";
    }

}

ejbModule.obj

package ejbModule.obj;

import ejbModule.interfaces.SrzedObjInterface;
import java.io.Serializable;

public class SrzedObj implements SrzedObjInterface, Serializable {

    protected String TheString = "This is the string I want";

    @Override
    public String getTheString() {
        return TheString;
    }

}

Web 项目包括 JSF 库，并具有以下类和测试网页，以及标准 beans.xml 文件（未显示）和 web.xml 文件（未显示）：

webModule.webbean

package webModule;

import ejbModule.interfaces.ABeanInterface;
import ejbModule.interfaces.SrzedObjInterface;
import javax.ejb.EJB;
import javax.enterprise.context.RequestScoped;
import javax.inject.Named;

@Named
@RequestScoped
public class webbean {

    @EJB
    private ABeanInterface ABeanInstance;

    // The string I want
    public String getStringViaObject() {
        // Code that produces the error
        // ----------------------------
        //SrzedObjInterface SrzedObject = ABeanInstance.getObject(); // Throws the NullPointerException
        //return SrzedObject.getAString();
        // ----------------------------

        return "";
    }

    // The string that I don't want
    public String getString() {
        return ABeanInstance.getString();
    }

    // Also not the string I want, but here to show that this is possible
    public String getLocalString() {
        return "The local string";
    }

}

索引.xhtml

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
  xmlns:h="http://java.sun.com/jsf/html"
  xmlns:ui="http://java.sun.com/jsf/facelets"
  xmlns:c="http://java.sun.com/jsp/jstl/core">

    <h:head>

    </h:head>

    <h:body>

        <h1>The strings</h1>

        <p>The local string: <h:outputText value="#{webbean.localString}"/></p>
        <p>The string: <h:outputText value="#{webbean.string}"/></p>
        <p>The string from the object: <h:outputText value="#{webbean.stringViaObject}"/></p>

    </h:body>

</html>

除了 Netbeans 为我包含的标准文件之外，仅此而已。

由此产生的堆栈跟踪（引入了问题代码）是：

SEVERE: Error Rendering View[/index.xhtml]
javax.el.ELException: /index.xhtml @18,90 value="#{webbean.stringViaObject}": java.lang.NullPointerException
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIOutput.getValue(UIOutput.java:169)
at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:205)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:355)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:164)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1764)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:288)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:722)

Caused by: java.lang.NullPointerException
at com.sun.corba.ee.impl.orbutil.ClassInfoCache$ClassInfo.<init>(ClassInfoCache.java:156)
at com.sun.corba.ee.impl.orbutil.ClassInfoCache.get(ClassInfoCache.java:281)
at com.sun.corba.ee.impl.encoding.CDRInputStream_1_0.read_value(CDRInputStream_1_0.java:1097)
at com.sun.corba.ee.impl.encoding.CDRInputObject.read_value(CDRInputObject.java:531)
at com.sun.corba.ee.impl.presentation.rmi.DynamicMethodMarshallerImpl$14.read(DynamicMethodMarshallerImpl.java:384)
at com.sun.corba.ee.impl.presentation.rmi.DynamicMethodMarshallerImpl.readResult(DynamicMethodMarshallerImpl.java:483)
at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:203)
at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.invoke(StubInvocationHandlerImpl.java:152)
at com.sun.corba.ee.impl.presentation.rmi.codegen.CodegenStubBase.invoke(CodegenStubBase.java:227)
at ejbModule.interfaces.__ABeanInterface_Remote_DynamicStub.getObject(ejbModule/interfaces/__ABeanInterface_Remote_DynamicStub.java)
at ejbModule.interfaces._ABeanInterface_Wrapper.getObject(ejbModule/interfaces/_ABeanInterface_Wrapper.java)
at webModule.webbean.getStringViaObject(webbean.java:18)
at webModule.webbean$Proxy$_$$_WeldClientProxy.getStringViaObject(webbean$Proxy$_$$_WeldClientProxy.java)
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:601)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at com.sun.el.parser.AstValue.getValue(AstValue.java:138)
at com.sun.el.parser.AstValue.getValue(AstValue.java:183)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:224)
at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
... 41 more

非常感谢任何有耐心阅读所有内容的人！我真的很感激任何帮助。

4

1 回答 1

1

你不需要分享SrzedObj吗？Web 层无法反序列化其具体类不可用的东西...中的 NPEClassInfoCache.java:156似乎与此问题中的错误相同。

于 2013-05-22T08:55:19.723 回答