我在WildFly 8.2上运行Java EE 7应用程序。我使用OmniFaces 1.8.1。
我在与NullPointerExceptions相关的日志文件FacesViewsForwardingFilter中看到：
2015-02-11 15:42:22,870 ERROR [io.undertow.request] (default task-12) UT005023: Exception handling request to /login: java.lang.NullPointerException
at org.omnifaces.facesviews.FacesViewsForwardingFilter.doFilter(FacesViewsForwardingFilter.java:122) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:132) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
2015-02-11 15:42:31,524 ERROR [io.undertow.request] (default task-15) UT005023: Exception handling request to /search.xhtml: java.lang.NullPointerException
at org.omnifaces.facesviews.FacesViewsForwardingFilter.doFilter(FacesViewsForwardingFilter.java:153) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
在服务器启动期间，我看到以下信息：
2015-02-11 12:28:35,667 ERROR [io.undertow.request] (default task-3) UT005023: Exception handling request to /terms/index: java.lang.IllegalStateException: Illegal attempt to set ViewHandler after a response has been rendered.
at com.sun.faces.application.ApplicationImpl.setViewHandler(ApplicationImpl.java:583) [jsf-impl-2.2.8-jbossorg-1.jar:]
at javax.faces.application.ApplicationWrapper.setViewHandler(ApplicationWrapper.java:288) [jboss-jsf-api_2.2_spec-2.2.8.jar:2.2.8]
at org.jboss.as.jsf.injection.weld.ForwardingApplication.setViewHandler(ForwardingApplication.java:367) [wildfly-jsf-injection-8.2.0.Final.jar:8.2.0.Final]
at org.omnifaces.facesviews.FacesViewsForwardingFilter.init(FacesViewsForwardingFilter.java:95) [omnifaces-1.8.1.jar:1.8.1-20140603]
at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:111) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
at org.wildfly.extension.undertow.security.RunAsLifecycleInterceptor.init(RunAsLifecycleInterceptor.java:85)
web.xml中的相关配置为：<servlet>
<servlet-name>facesServlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>facesServlet</servlet-name>
<url-pattern>*.html</url-pattern>
<url-pattern>*.xhtml</url-pattern>
<url-pattern>/javax.faces.resource/*</url-pattern>
</servlet-mapping>
<context-param>
<param-name>org.omnifaces.FACES_VIEWS_SCAN_PATHS</param-name>
<param-value>/*.xhtml</param-value>
</context-param>
这是怎么引起的，我该如何解决？
最佳答案
这些NPE表明过滤器的初始化失败。在服务器启动期间，您应该能够在日志中更早地找到线索。
2015-02-11 12：28：35,667错误[io.undertow.request]（默认任务3）UT005023：对/ terms / index的异常处理请求：java.lang.IllegalStateException：响应尝试后非法尝试设置ViewHandler被渲染。IllegalStateException是有用的提示。 FacesViewsViewHandler在OmniFaces 1.x中通过FacesViewsForwardingFilter在与/*.xhtml匹配的URL上第一次请求时被延迟初始化。但是，如果在过滤器之前调用FacesServlet，则由于该异常而失败。您有一个可疑的*.html映射，该映射将触发FacesServlet而不触发过滤器。您是否有一个纯HTML页面作为欢迎文件？为什么不将其重命名为*.xhtml？
无论如何，该初始化排序错误是OmniFaces 2.0中的fixed。因此，升级应该可以。