NPE試圖渲染春天的Webflow

視圖時嘗試使用的Webflow，我不斷收到以下錯誤：NPE試圖渲染春天的Webflow

{ 
    "failure":"true", 
    "exception.message":"org.springframework.webflow.execution.ActionExecutionException: Exception thrown executing [email protected]5beb in state 'accountCannotLogInView' of flow 'login' -- action execution attributes were 'map[[empty]]'", 
    "exception.stacktrace":"org.springframework.webflow.execution.ActionExecutionException: Exception thrown executing [email protected]5beb in state 'accountCannotLogInView' of flow 'login' -- action execution attributes were 'map[[empty]]' 
    ... 
    Caused by: java.lang.IllegalStateException: Exception occurred rendering view null 
     at org.springframework.webflow.mvc.view.AbstractMvcView.render(AbstractMvcView.java:191) 
     at org.springframework.webflow.action.ViewFactoryActionAdapter.doExecute(ViewFactoryActionAdapter.java:40) 
     at org.springframework.webflow.action.AbstractAction.execute(AbstractAction.java:188) 
     at org.springframework.webflow.execution.ActionExecutor.execute(ActionExecutor.java:51) 
     ... 66 more 
    Caused by: java.lang.NullPointerException 
     at org.springframework.webflow.mvc.servlet.ServletMvcView.doRender(ServletMvcView.java:50) 
     at org.springframework.webflow.mvc.view.AbstractMvcView.render(AbstractMvcView.java:187) 
     ... 69 more 
    " 
}

沒有任何人有任何想法，這樣做的原因可能是什麼？從我的login-webflow.xml：

<action-state id="checkAccountType"> 
    <evaluate expression="lookupAccountTypeAction.lookup(flowScope.principal)" /> 
    <transition on="EMAIL" to="accountCannotLogInView" /> 
    <transition on="Login" to="checkAccountStatus" /> 
    <transition on="CONTACT" to="accountCannotLogInView" /> 
</action-state> 

<end-state id="accountCannotLogInView" view="myAccountCannotLogInView"/>

從default_views.properties：

myAccountCannotLogInView.(class)=org.springframework.web.servlet.view.JstlView 
myAccountCannotLogInView.url=/WEB-INF/view/jsp/default/ui/myAccountCannotLogInView.jsp

從我的日誌文件：

2013-09-09 08:29:25,645 DEBUG [org.springframework.webflow.engine.EndState] - Entering state 'accountCannotLogInView' of flow 'login' 
2013-09-09 08:29:25,645 DEBUG [org.springframework.webflow.execution.ActionExecutor] - Executing [email protected]136a 
2013-09-09 08:29:25,645 DEBUG [org.springframework.webflow.mvc.view.AbstractMvcView] - Rendering MVC [null] with model map [{flowRequestContext=[[email protected] externalContext = [email protected]74, currentEvent = EMAIL, requestScope = map['ticketGrantingTicketId' -> 'TGT-1-GxALVR7PEtbagbnRlStOTbHoRHlb61YVm1m2hvWx3pgWCEXgPb-cas01.example.org'], attributes = map[[empty]], messageContext = [[email protected] sourceMessages = map[[null] -> list[[empty]]]], flowExecution = [[email protected] flow = 'login', flowSessions = list[[[email protected] flow = 'login', state = 'accountCannotLogInView', scope = map['principal' -> sso_test_user, 'userInfoBean' -> [email protected][username=<null>,firstName=<null>,lastName=<null>,emailAddress=<null>,streetAddress=<null>,city=<null>,state=<null>,zip=<null>,country=<null>], 'changePasswordBean' -> com.mycompany.authentication.ChangePasswordBean(username=null, newPassword=null, confirmNewPassword=null), 'service' -> https://my.server.com:443/casauth/facade/norenew?idp=https://my.server.com/idp/externalAuthnCallback, 'credentials' -> [username: sso_test_user], 'warnCookieValue' -> false, 'ticketGrantingTicketId' -> 'TGT-1-GxALVR7PEtbagbnRlStOTbHoRHlb61YVm1m2hvWx3pgWCEXgPb-cas01.example.org']]]]], flashScope=map[[empty]], principal=sso_test_user, currentUser=null, [email protected][username=<null>,firstName=<null>,lastName=<null>,emailAddress=<null>,streetAddress=<null>,city=<null>,state=<null>,zip=<null>,country=<null>], changePasswordBean=com.mycompany.authentication.ChangePasswordBean(username=null, newPassword=null, confirmNewPassword=null), service=https://my.server.com:443/casauth/facade/norenew?idp=https://my.server.com/idp/externalAuthnCallback, credentials=[username: sso_test_user], flowExecutionKey=e1s1, warnCookieValue=false, flowExecutionUrl=/authentication/login?username=%5BLjava.lang.String%3B%405b65afa5&submit=%5BLjava.lang.String%3B%4070eea883&_eventId=%5BLjava.lang.String%3B%4044796a61&service=%5BLjava.lang.String%3B%407f372965&lt=%5BLjava.lang.String%3B%407e7ee722&password=%5BLjava.lang.String%3B%403d78aa0f&execution=%5BLjava.lang.String%3B%403ce4de50, ticketGrantingTicketId=TGT-1-GxALVR7PEtbagbnRlStOTbHoRHlb61YVm1m2hvWx3pgWCEXgPb-cas01.example.org}] 
2013-09-09 08:29:25,645 DEBUG [org.springframework.webflow.engine.impl.FlowExecutionImpl] - Attempting to handle [org.springframework.webflow.execution.ActionExecutionException: Exception thrown executing [email protected]136a in state 'accountCannotLogInView' of flow 'login' -- action execution attributes were 'map[[empty]]'] with root cause [java.lang.NullPointerException] 
2013-09-09 08:29:25,645 DEBUG [org.springframework.webflow.engine.impl.FlowExecutionImpl] - Rethrowing unhandled flow execution exception

是的，該文件確實存在該位置。我一直在這裏喋喋不休幾天，所以如果有人有任何見解，我會非常感激。

來源

2013-08-27 Eric Stein

我不明白你應該如何獲得屬性值到你的flow.xml，但你有沒有嘗試過使用硬編碼路徑？或者你有沒有嘗試在你的狀態下添加'.url'？ –

我不知道 - CAS處理。我對CAS和Spring Webflow都很陌生，現在也不會特別激動。 :-)你的意思是有一種方法可以將URL直接放入標籤中？ –

它適用於我的應用程序 –

和正確的答案是「用戶錯誤」。我正在通過maven構建CAS。我創建了配置文件來保存日誌記錄，然後錯誤地配置它以使default_views.properties文件不在配置文件中。因此，當CAS在Maven構建中覆蓋它時，它包含了基線default_views.properties而不是我的副本。

來源

2013-09-09 16:18:05

好像你的屬性沒有被解析到你的flow.xml中。

定義你的硬編碼視圖應該工作。

在這裏看到：Specifying view identifiers

來源

2013-08-28 15:36:11

不幸的是，它沒有。我仍然得到NPE。 :-( –

因爲你把我推向了正確的方向，我會把賞金獎給你，我只需要等22個小時就可以做到。 –

非常感謝你！ –

此問題的原因是：未找到JSP視圖。

在CAS-servlet.xml中，提到其具有定製JSP視圖的「視圖解析器」豆如下內的基名屬性文件：

<bean id="viewResolver" 
    class="org.springframework.web.servlet.view.ResourceBundleViewResolver" 
    p:order="0"> 
    <property name="basenames"> 
     <util:list> 
      <value>${cas.viewResolver.basename}</value> 
      <value>custom_view</value> 
      <value>protocol_views</value> 
     </util:list> 
    </property> 
</bean>

而在custom_view.properties，提及以下：

casRegisterView.(class)=org.springframework.web.servlet.view.JstlView 
casRegisterView.url=/WEB-INF/view/jsp/default/ui/casRegisterView.jsp

這裏的JSP視圖是「casRegisterView.jsp」。將custom_view.properties放置在/ src/main/resources中。

來源

2015-07-16 09:25:59

NPE試圖渲染春天的Webflow

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