问题
I have created two jsf projects in JSF. One of them is a base project that has a single session bean. This base project is packaged into a .jar file (with a /META-INF/faces-config.xml file) and included in the other project (the clientproj). The problem is that when I run the client project, the session bean in the base project is not instantiated, and I get a NullPointerException.
Details are as follows:
Base Project - Session 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";
}
}
The META-INF/faces-config.xml file in this project is as follows:
<?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">
(The META-INF folder is under the WebContent folder).
This project is exported as a .jar file named sbeans.jar (using eclipse) by right clicking on th project --> export --> export --> jar file.
Now there is a client project where sbeans.jar is placed in the WEB-INF/lib folder. The client project has a single bean as follows:
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;
}
}
The client project has a test.xhtml as follows:
<!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>
When I try to run test.xhtml (on tomcat, within eclipse), I get an exception as follows (presumably due the sessionBean being null (see text in bold)):
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)
BTW, there is also a simple result.xhtml in the client project as follows:
<!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>
The original project where I need this working is a lot more complicated than this. What I have posted here is the crux of the issue I am facing. I have struggled with this for quite a few hours, and have tried many different methods to get this working. Any help will be much appreciated.
Thanks Mahendra
回答1:
Looks like Base project - the one with session bean is not correctly exported. JSF requires faces-config.xml to be placed in sbeans.jar directly in META-INF directory. However, according to your description Base project is a web project. When I created such project and exported it using the way you did I got the following structure:
sbeans.jar
|--META-INF (empty)
|--WebContent
|--META-INF
|--faces-config.xml
As you see faces-config.xml is placed in wrong place.
To fix this either:
- change project type to plain java - you anyway export it as JAR not WAR, don't you? (looks like the only way to do it is to create new project from scratch). Then you can then use the following hint https://stackoverflow.com/a/11027541/1071508 to generate WAR with all dependencies with only few mouse clicks.
- if changing project type is not possible consider converting projects to maven so that you take advantage of plugins. Then you can rename the WAR during creation: Renaming Maven dependency in WAR's WEB-INF/lib folder
- if previous solution is not possible for some reason
- create
META-INFinJava Resources/srcand placefaces-config.xmlthere - or export project as WAR and rename it to
.jarafter exporting
- create
来源：https://stackoverflow.com/questions/28655154/jsf-managed-bean-in-jar-not-instantiated