Servlet Faces Servlet的Servlet.service()引发异常:java.lang.NullPointerException JSF [英] Servlet.service() for servlet Faces Servlet threw exception: java.lang.NullPointerException JSF
本文介绍了Servlet Faces Servlet的Servlet.service()引发异常:java.lang.NullPointerException JSF的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
是否已解决以下错误.当我单击命令按钮时，它将调用Java脚本来设置topic_body，topic_url的值，并通过命令按钮将这些值提交到服务器中的方法.我不确定要纠正此错误才能停止此错误.
XHTML
<h:form prependId="false" id="testForm">
<h:inputHidden value="#{topicBean.topicVO.body}" id="topic_body">
</h:inputHidden>
<h:inputHidden value="#{topicBean.topicVO.videoAudioUrl}" id="topic_vaurl" >
</h:inputHidden>
<h:inputHidden value="#{topicBean.topic_guid}" id="topic_guid">
</h:inputHidden>
<p:commandButton id="shareeButton" action="#{topicController.createTopic}" onclick="javascript:renderElement();">
Share
<f:ajax execute="@form" render="@form"></f:ajax>
</p:commandButton>
</h:form>
JavaScript
function renderElement(){
var textarea_content = $('textarea#wall').val();
$('#topic_body').val(textarea_content);
if (textarea_content != '') {
var sitetitle = $('label.title').html();
if (sitetitle == null) {
sitetitle = ' ';
}
.......
......
..
}
JSF Bean
@ManagedBean(name = "topicBean")
@SessionScoped
public class TopicBean extends BaseMB implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private final static Logger logger = Logger.getLogger(CircleBean.class.toString());
private TopicVO topicVO = new TopicVO();
private long topic_guid =0;
public TopicBean(){
logger.info("****************************Start TopicBean Constructor****************************************");
logger.info("****************************End TopicBean Constructor****************************************");
}
JSF方法
@ManagedBean(name = "topicController")
@RequestScoped
public class TopicController extends BaseMB implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private final static Logger logger = Logger
.getLogger(CircleController.class.toString());
TopicBean topicBean;
public void createTopic(){
logger.info("*******************Inside creatTopic********************");
topicBean = (TopicBean) FacesUtils.getManagedBean("topicBean");
ITopicService topicService = (ITopicService) ServiceLocator
.getService("TOPICSERVICE");
topicBean.setTopic_guid(topicService.createTopic(topicBean.getTopicVO(), userSession));
logger.info("*******************Inside creatTopic********************");
}
错误
14:44:20,335 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/emyed-web].[Faces Servlet]] (http--127.0.0.1-8080-3) Servlet.service() for servlet Faces Servlet threw exception: java.lang.NullPointerException
at com.sun.faces.mgbean.BeanManager$ScopeManager$SessionScopeHandler.handle(BeanManager.java:575) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager$ScopeManager.pushToScope(BeanManager.java:458) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:410) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.hasLoggedIn(EmyEdAccessFilter.java:113) [emyed-ui-1.0.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.doFilter(EmyEdAccessFilter.java:84) [emyed-ui-1.0.jar:]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:897) [jbossweb-7.0.13.Final.jar:]
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:626) [jbossweb-7.0.13.Final.jar:]
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:2039) [jbossweb-7.0.13.Final.jar:]
at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_25]
enter code here
解决方案
根据堆栈跟踪，
java.lang.NullPointerException
at com.sun.faces.mgbean.BeanManager$ScopeManager$SessionScopeHandler.handle(BeanManager.java:575) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager$ScopeManager.pushToScope(BeanManager.java:458) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:410) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.hasLoggedIn(EmyEdAccessFilter.java:113) [emyed-ui-1.0.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.doFilter(EmyEdAccessFilter.java:84) [emyed-ui-1.0.jar:]
您有一个Filter类EmyEdAccessFilter，它试图使用ValueExpression解析特定于JSF的EL表达式，最可能的目的是查找会话范围内的JSF托管Bean或其属性，该属性应表示登录的用户.但是，此EL解决方法失败了，因为servlet过滤器中没有FacesContext的意思. FacesContext应该由FacesServlet创建，但是在过滤器运行的那一刻，FacesServlet根本没有运行，因此FacesContext.getCurrentInstance()返回null，因此代码中断了. /p>
总而言之，这不是在过滤器中检查会话范围内的JSF托管bean的正确方法.
在JSF的介绍下，以会话为范围的托管Bean作为HttpSession的属性存储，以托管Bean名称作为会话属性名称.您只需以通常的方式"将它们作为servlet过滤器中的会话属性进行访问.例如
@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
HttpSession session = request.getSession(false);
UserManager userManager = (session != null) ? (UserManager) session.getAttribute("userManager") : null;
if (userManager == null || !userManager.isLoggedIn()) {
response.sendRedirect(request.getContextPath() + "/login.xhtml"); // No logged-in user found, so redirect to login page.
} else {
chain.doFilter(req, res); // Logged-in user found, so just continue request.
}
}
其中UserManager表示您的会话范围内的JSF托管Bean.
另请参见:
Is there a fix to the below error. When i click the command button it calls the java script to set the values for topic_body,topic_url and submit the values to a method in server by the commandbutton. I am not sure what was need to be corrected to stop the error.
XHTML
<h:form prependId="false" id="testForm">
<h:inputHidden value="#{topicBean.topicVO.body}" id="topic_body">
</h:inputHidden>
<h:inputHidden value="#{topicBean.topicVO.videoAudioUrl}" id="topic_vaurl" >
</h:inputHidden>
<h:inputHidden value="#{topicBean.topic_guid}" id="topic_guid">
</h:inputHidden>
<p:commandButton id="shareeButton" action="#{topicController.createTopic}" onclick="javascript:renderElement();">
Share
<f:ajax execute="@form" render="@form"></f:ajax>
</p:commandButton>
</h:form>
Javascript
function renderElement(){
var textarea_content = $('textarea#wall').val();
$('#topic_body').val(textarea_content);
if (textarea_content != '') {
var sitetitle = $('label.title').html();
if (sitetitle == null) {
sitetitle = ' ';
}
.......
......
..
}
JSF Bean
@ManagedBean(name = "topicBean")
@SessionScoped
public class TopicBean extends BaseMB implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private final static Logger logger = Logger.getLogger(CircleBean.class.toString());
private TopicVO topicVO = new TopicVO();
private long topic_guid =0;
public TopicBean(){
logger.info("****************************Start TopicBean Constructor****************************************");
logger.info("****************************End TopicBean Constructor****************************************");
}
JSF Method
@ManagedBean(name = "topicController")
@RequestScoped
public class TopicController extends BaseMB implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private final static Logger logger = Logger
.getLogger(CircleController.class.toString());
TopicBean topicBean;
public void createTopic(){
logger.info("*******************Inside creatTopic********************");
topicBean = (TopicBean) FacesUtils.getManagedBean("topicBean");
ITopicService topicService = (ITopicService) ServiceLocator
.getService("TOPICSERVICE");
topicBean.setTopic_guid(topicService.createTopic(topicBean.getTopicVO(), userSession));
logger.info("*******************Inside creatTopic********************");
}
ERROR
14:44:20,335 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/emyed-web].[Faces Servlet]] (http--127.0.0.1-8080-3) Servlet.service() for servlet Faces Servlet threw exception: java.lang.NullPointerException
at com.sun.faces.mgbean.BeanManager$ScopeManager$SessionScopeHandler.handle(BeanManager.java:575) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager$ScopeManager.pushToScope(BeanManager.java:458) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:410) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.hasLoggedIn(EmyEdAccessFilter.java:113) [emyed-ui-1.0.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.doFilter(EmyEdAccessFilter.java:84) [emyed-ui-1.0.jar:]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:897) [jbossweb-7.0.13.Final.jar:]
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:626) [jbossweb-7.0.13.Final.jar:]
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:2039) [jbossweb-7.0.13.Final.jar:]
at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_25]
enter code here
解决方案
According to the stacktrace,
java.lang.NullPointerException
at com.sun.faces.mgbean.BeanManager$ScopeManager$SessionScopeHandler.handle(BeanManager.java:575) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager$ScopeManager.pushToScope(BeanManager.java:458) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:410) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.hasLoggedIn(EmyEdAccessFilter.java:113) [emyed-ui-1.0.jar:]
at com.zreflect.emyed.filter.EmyEdAccessFilter.doFilter(EmyEdAccessFilter.java:84) [emyed-ui-1.0.jar:]
you've a Filter class EmyEdAccessFilter which is trying to resolve a JSF-specific EL expression using ValueExpression, most likely with the sole purpose to find a session scoped JSF managed bean or its property which should represent the logged-in user. But this EL resolving failed because there's no means of a FacesContext inside a servlet filter. The FacesContext is supposed to be created by the FacesServlet, but at the moment the filter runs, the FacesServlet hasn't run at all and thus the FacesContext.getCurrentInstance() returns null and thus your code breaks.
All with all, this is not the right way to check a session scoped JSF managed bean in a filter.
Under JSF's covers, session scoped managed beans are stored as attributes of the HttpSession with the managed bean name as session attribute name. You can just access them "the usual way" as session attributes in a servlet filter. E.g.
@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
HttpSession session = request.getSession(false);
UserManager userManager = (session != null) ? (UserManager) session.getAttribute("userManager") : null;
if (userManager == null || !userManager.isLoggedIn()) {
response.sendRedirect(request.getContextPath() + "/login.xhtml"); // No logged-in user found, so redirect to login page.
} else {
chain.doFilter(req, res); // Logged-in user found, so just continue request.
}
}
Where UserManager represents your session scoped JSF managed bean.
See also:
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