1

我是春天的新手。我正在尝试使用 Tomcat 上的 Spring web flow 运行一个名为 library 的自学项目。作为 IDE，我使用 Eclipse Indigo。

我的项目的 WebContent 文件夹结构如下：

 WebContent
    pages
        welcome
            - introduction.jsp
            - menu.jsp
            - welcome.jsp
            - welcome.xml
    WEB-INF
        - library-service.xml
        - library-servlet.xml
        - library-webflow.xml
        - web.xml
        lib
            - commons-logging.jar
            - jstl.jar
            - ognl-2.6.9.jar
            - org.springframework.binding-2.0.9.RELEASE.jar
            - org.springframework.js-2.0.9.RELEASE.jar
            - org.springframework.webflow-2.0.9.RELEASE.jar
            - spring.jar
            - spring-webmvc.jar
            - standard.jar

作为内容web.xml，它如下：

<display-name>library</display-name>

<context-param>
    <param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/library-service.xml</param-value>
</context-param>

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
    <servlet-name>library</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>library</servlet-name>
    <url-pattern>/pages/*</url-pattern>
</servlet-mapping>

library-servlet.xml的内容如下：

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <import resource="library-webflow.xml" />   

</beans>

我使用library-service.xml从服务层向 bean 声明。其内容如下：

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<bean name="libraryService"
    class="com.library.service.LibraryService" />

</beans>

作为welcome.jsp页面的内容，如下：

<html>
<head>
<title>Welcome</title>
</head>
<body>
    <h2>Welcome!</h2>
    <a href="${flowExecutionUrl}&_eventId=next">Next</a>
    <a href="${flowExecutionUrl}&_eventId=skip">Skip</a>
</body>
</html>

由于welcome.xml的内容是：

<flow xmlns="http://www.springframework.org/schema/webflow"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/webflow
    http://www.springframework.org/schema/webflow/spring-webflow-2.0.xsd">

    <view-state id="welcome">
        <transition on="next" to="introduction" />
        <transition on="skip" to="menu" />
</view-state>

    <view-state id="introduction">
        <transition on="next" to="menu" />
    </view-state>

    <view-state id="menu" />
</flow>

我的问题是，当我运行welcome.jsp 时，在Tomcat 中出现以下嵌套错误。我正在使用 Tomcat 6.0.35。

Sep 19, 2012 4:41:11 PM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet library threw exception
java.lang.NullPointerException
    at org.springframework.webflow.conversation.impl.ContainedConversation.unlock(ContainedConversation.java:107)
    at org.springframework.webflow.execution.repository.support.ConversationBackedFlowExecutionLock.unlock(ConversationBackedFlowExecutionLock.java:55)
    at org.springframework.webflow.executor.FlowExecutorImpl.resumeExecution(FlowExecutorImpl.java:178)
    at org.springframework.webflow.mvc.servlet.FlowHandlerAdapter.handle(FlowHandlerAdapter.java:183)
    at org.springframework.webflow.mvc.servlet.FlowController.handleRequest(FlowController.java:174)
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:236)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:257)
    at org.springframework.webflow.mvc.servlet.ServletMvcView.doRender(ServletMvcView.java:50)
    at org.springframework.webflow.mvc.view.AbstractMvcView.render(AbstractMvcView.java:180)
    at org.springframework.webflow.engine.ViewState.render(ViewState.java:282)
    at org.springframework.webflow.engine.ViewState.refresh(ViewState.java:241)
    at org.springframework.webflow.engine.ViewState.resume(ViewState.java:219)
    at org.springframework.webflow.engine.Flow.resume(Flow.java:545)
    at org.springframework.webflow.engine.impl.FlowExecutionImpl.resume(FlowExecutionImpl.java:259)
    at org.springframework.webflow.executor.FlowExecutorImpl.resumeExecution(FlowExecutorImpl.java:169)
    at org.springframework.webflow.mvc.servlet.FlowHandlerAdapter.handle(FlowHandlerAdapter.java:183)
    at org.springframework.webflow.mvc.servlet.FlowController.handleRequest(FlowController.java:174)
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Unknown Source)

Sep 19, 2012 4:41:11 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet library threw exception
java.lang.NullPointerException
    at org.springframework.webflow.conversation.impl.ContainedConversation.unlock(ContainedConversation.java:107)
    at org.springframework.webflow.execution.repository.support.ConversationBackedFlowExecutionLock.unlock(ConversationBackedFlowExecutionLock.java:55)
    at org.springframework.webflow.executor.FlowExecutorImpl.resumeExecution(FlowExecutorImpl.java:178)
    at org.springframework.webflow.mvc.servlet.FlowHandlerAdapter.handle(FlowHandlerAdapter.java:183)
    at org.springframework.webflow.mvc.servlet.FlowController.handleRequest(FlowController.java:174)
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Unknown Source)

难道我做错了什么？

4

1 回答 1

0

尝试将 webflow XML 添加到 web.xml：

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/library-service.xml, /WEB-INF/library-webflow.xml</param-value>
</context-param>
于 2012-09-19T11:55:27.193 回答