servlet的Servlet.service（）Faces Servlet抛出异常：java.lang.NullPointerException JSF

时间：2012-08-27 19:06:48

标签： jsf jsf-2 primefaces

是否修复了以下错误。当我单击命令按钮时，它调用java脚本来设置topic_body，topic_url的值，并通过commandbutton将值提交给服务器中的方法。我不确定需要纠正什么来阻止错误。

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>

的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

2 个答案:

答案 0 :(得分：4)

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:]

你有Filter类EmyEdAccessFilter试图使用ValueExpression解析特定于JSF的EL表达式，最有可能的唯一目的是找到一个会话作用域的JSF托管bean或其属性应代表登录用户。但是这个EL解析失败了，因为在servlet过滤器中没有FacesContext的方法。 FacesContext应该由FacesServlet创建，但是当过滤器运行时，FacesServlet根本没有运行，因此FacesContext.getCurrentInstance()返回{{} 1}}因此您的代码会中断。

总而言之，这不是在过滤器中检查会话范围的JSF托管bean的正确方法。

在JSF的涵盖下，会话范围的托管bean作为null的属性存储，托管bean名称作为会话属性名称。您可以“通常的方式”访问它们作为servlet过滤器中的会话属性。 E.g。

HttpSession

其中@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. } } 表示会话作用域的JSF托管bean。

另见：

答案 1 :(得分：0)

同时检查@ManagedProperty是否正确。例如：

@ManagedProperty(value = "#{user_ejb}")
UserEJB userEJB;

或@Inject

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