JSF托管bean在jar中没有实例化

时间：2015-02-22 06:19:23

标签： jsf jar javabeans managed

我在JSF中创建了两个jsf项目。其中一个是具有单个会话bean的基础项目。此基础项目打包到.jar文件（带有/META-INF/faces-config.xml文件）中，并包含在另一个项目（clientproj）中。问题是当我运行客户端项目时，基础项目中的会话bean没有实例化，我得到一个NullPointerException。

详情如下：

基础项目 - 会话Bean 

package sbeans;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean
@SessionScoped
public class SessionBean {

private String myName;

public String getMyName()
{
    return this.myName;
}

public void setMyName(String newName)
{
    this.myName = newName;
}

public String getResult()
{
    return "result";
}

}

此项目中的META-INF / faces-config.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<faces-config
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee                http://xmlns.jcp.org/xml/ns/javaee/web-facesconfig_2_2.xsd"
version="2.2">

（META-INF文件夹位于WebContent文件夹下）。

通过右键单击项目，将该项目导出为名为sbeans.jar的.jar文件（使用eclipse） - ＆gt;出口 - ＆gt;出口 - ＆gt; jar文件。

现在有一个客户端项目，其中sbeans.jar放在WEB-INF / lib文件夹中。客户端项目有一个bean，如下所示：

package clientproj;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;

import sbeans.SessionBean;

@ManagedBean
public class ClientBean {

@ManagedProperty("#{sessionBean}") private SessionBean sessionBean;

private String name;

public String getName()
{
    System.out.println("clientBean.getName() - this.sessionBean = " + this.sessionBean);
    this.name = this.sessionBean.getMyName();
    return this.name;
}

public void setName(String newName)
{
    this.name = newName;
    System.out.println("clientBean.setName() - this.sessionBean = " + this.sessionBean);
    this.sessionBean.setMyName(this.name);
}

public void setSessionBean(SessionBean sBean)
{
    this.sessionBean = sBean;
}

}

客户端项目的test.xhtml如下：

<!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:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">

<h:head>
<title>Some Title</title>
</h:head>

<h:body>

<h:form>
<h:outputLabel value="Enter Your Name" for="name"></h:outputLabel>
<br></br>
<h:inputText value="#{clientBean.name}"></h:inputText>
<h:commandButton value="Go" action="#{sessionBean.getResult}">        </h:commandButton>
</h:form>

</h:body>
</html>

当我尝试运行test.xhtml（在tomcat上，在eclipse中）时，我得到如下异常（可能是因为sessionBean为null（参见粗体文本））：

Feb 22, 2015 12:50:02 AM com.sun.faces.renderkit.html_basic.HtmlBasicRenderer getForComponent
WARNING: Unable to find component with ID name in view.
**clientBean.getName() - this.sessionBean = null**
Feb 22, 2015 12:50:02 AM   com.sun.faces.application.view.FaceletViewHandlingStrategy handleRenderException
SEVERE: Error Rendering View[/test.xhtml]
javax.el.ELException: /test.xhtml @18,41 value="#{clientBean.name}": Error   reading 'name' on type clientproj.ClientBean
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:174)
at javax.faces.component.UIInput.getValue(UIInput.java:291)
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:924)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:894)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:443)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.el.ELException: Error reading 'name' on type   clientproj.ClientBean
at javax.el.BeanELResolver.getValue(BeanELResolver.java:110)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstValue.getValue(AstValue.java:183)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
... 40 more
Caused by: java.lang.NullPointerException
at clientproj.ClientBean.getName(ClientBean.java:18)
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.BeanELResolver.getValue(BeanELResolver.java:99)
... 45 more

Feb 22, 2015 12:50:02 AM org.apache.catalina.core.StandardWrapperValve   invoke
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path     [/clientproj] threw exception [null] with root cause
java.lang.NullPointerException
at clientproj.ClientBean.getName(ClientBean.java:18)
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.BeanELResolver.getValue(BeanELResolver.java:99)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstValue.getValue(AstValue.java:183)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
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:174)
at javax.faces.component.UIInput.getValue(UIInput.java:291)
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:924)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:894)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:443)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

顺便说一下，客户端项目中还有一个简单的result.xhtml如下：

<!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:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">
<h:head>
<title>Result</title></h:head>

<h:body>
<h1>Result</h1>
<h2>
<h:outputText value="#{clientBean.name}"></h:outputText>
</h2>
</h:body>
</html>

我需要这项工作的原始项目比这复杂得多。我在这里发布的是我面临的问题的症结所在。我已经挣扎了好几个小时，并尝试了许多不同的方法来实现这个目标。任何帮助将不胜感激。

由于 马亨德拉

1 个答案:

答案 0 :(得分：1)

看起来像Base项目 - 没有正确导出会话bean的项目。 JSF要求faces-config.xml直接放在sbeans.jar META-INF目录中。但是，根据您的描述，Base项目是一个Web项目。当我创建这样的项目并使用你的方式导出它时，我得到了以下结构：

sbeans.jar
  |--META-INF (empty)
  |--WebContent
       |--META-INF
            |--faces-config.xml

如您所见faces-config.xml放在错误的位置。

要解决此问题：

  • 将项目类型更改为普通java - 您无论如何将其导出为JAR而不是WAR，不是吗？ （看起来这样做的唯一方法是从头开始创建新项目）。然后，您可以使用以下提示https://stackoverflow.com/a/11027541/1071508生成具有所有依赖关系的WAR，只需点击几下鼠标。
  • 如果无法更改项目类型，请考虑将项目转换为maven，以便利用插件。然后，您可以在创建期间重命名WAR：Renaming Maven dependency in WAR's WEB-INF/lib folder
  • 如果出于某种原因无法使用先前的解决方案
    • 在META-INF中创建Java Resources/src并将faces-config.xml放在那里
    • 或将项目导出为WAR，并在导出后将其重命名为.jar
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