运行 Spring 项目时出现空指针异常答案

【问题标题】：Null pointer exception while running Spring project运行 Spring 项目时出现空指针异常
【发布时间】：2014-06-10 14:54:18
【问题描述】：

我无法在我的 Spring 项目中找出 NullPointer 异常的原因。有时项目工作正常，但有时它在这里抛出空指针异常是完整的堆栈跟踪。

org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:585)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:455)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:322)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:184)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:155)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)

root cause

javax.servlet.ServletException: java.lang.NullPointerException
org.apache.jsp.redirect_jsp._jspService(index_jsp.java:72)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:322)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:184)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:155)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)

root cause

 java.lang.NullPointerException
org.apache.catalina.session.ManagerBase.generateSessionId(ManagerBase.java:807)
org.apache.catalina.session.ManagerBase.createSession(ManagerBase.java:653)
org.apache.catalina.connector.Request.doGetSession(Request.java:2892)
org.apache.catalina.connector.Request.getSession(Request.java:2315)
org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:898)
org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:910)
javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:238)
javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:238)
org.apache.jasper.runtime.PageContextImpl._initialize(PageContextImpl.java:146)
org.apache.jasper.runtime.PageContextImpl.initialize(PageContextImpl.java:125)
org.apache.jasper.runtime.JspFactoryImpl.internalGetPageContext(JspFactoryImpl.java:112)
org.apache.jasper.runtime.JspFactoryImpl.getPageContext(JspFactoryImpl.java:65)
org.apache.jsp.redirect_jsp._jspService(redirect_jsp.java:53)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:322)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:184)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:155)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)

我也经常收到 permgenspace 错误。与此有关吗？我将项目和 tomcat VM 选项（使用 NetBean IDE）更改为：

-XX:MaxPermSize=512m

我正在使用 Netbeans IDE 7.3.1、Apache Tomcat 7.0.37、Spring 3.1.1、Hibernate 3。

它在异常中显示 DelegatingFilterProxy。可能是因为安全设置。

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns:security="http://www.springframework.org/schema/security"
   xsi:schemaLocation="http://www.springframework.org/schema/beans 
   http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
   http://www.springframework.org/schema/security 
   http://www.springframework.org/schema/security/spring-security-3.1.xsd">

<!-- This is where we configure Spring-Security  -->
<security:http auto-config="true" use-expressions="true" access-denied-page="/auth/denied" >
    <security:intercept-url pattern="/admin/**" access="hasRole('ROLE_ADMIN')"/>
    <security:intercept-url pattern="/auth/**" access="hasRole('ROLE_USER')"/>
    <security:form-login
        login-page="/index"
        authentication-failure-url="/index"
        default-target-url="/welcome"
        />
    <security:logout
        invalidate-session="true"
        logout-success-url="/index" />
</security:http>


<!-- A custom service where Spring will retrieve users and their corresponding access levels  -->
<bean id="loginService" class="com.tcs.ignite.ih.spring.service.LoginService"/>

<!--A service where spring will redirect to proper view after successfull login-->
<!--<bean id="loginSuccessHandler" class="com.tcs.ignite.ih.spring.controller.LoginSuccessHandler" />-->

<!-- Declare an authentication-manager to use a custom userDetailsService -->
<security:authentication-manager>
    <security:authentication-provider user-service-ref="loginService">
    </security:authentication-provider>
</security:authentication-manager>

</beans>

更新：

当我尝试访问索引文件时，欢迎使用 web.xml 中定义的应用程序文件，并使用以下 URL

localhost:8080/xxxx/index

我在浏览器上收到以下信息：

HTTP Status 500 - Could not get RequestDispatcher for [/WEB-INF/jsp/index.jsp]: Check that the corresponding file exists within your web application archive!

index.jsp 在我的目录中。我需要在 /index 的 Spring Security 拦截 url 标签中定义映射吗？

【问题讨论】：

如果没有关于您的问题的明确信息，很难回答其他人。您能否详细说明您的问题，例如您在哪里收到此错误？什么时候将war文件部署到jboss中？像jboss版本，eclipse版本的所有配置是什么。
你的网页内容中有redirect.jsp吗？？
那么发生的事情是你的redirect.jsp 中有一个scriptlet，它在某些情况下会抛出一个空指针异常。可能您正在访问一个为空的请求属性并对其执行操作。尝试在页面中添加一些空检查。
好的@AdityaKeyal。谢谢，我会检查的。
@AdityaKeyal 我删除了 null RequestAttributes，但我仍然面临这个问题。

标签： java spring exception tomcat

【解决方案1】：

您是否在应用程序上下文中为 jsp 配置了视图解析器？如下所示

<bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="prefix" value="/pages/" />
            <property name="suffix" value=".jsp" />
            <property name="exposeContextBeansAsAttributes" value="true"/> 
</bean>

如果已配置，则检查控制器是否具有正确的定义。如果上述执行正确，则应该是spring security配置。

【讨论】：

【解决方案2】：

您的问题的根本原因是 tomcat ManagerBase 中的空 sessionIdGenerator。

快速查看code：可能只是Manager 尚未启动，或者它已经停止。我的猜测是您的代码正在使用“已经停止”的管理器。

如果我错了，请纠正我，但我猜你只有在取消部署/部署你的应用程序（没有完全重新启动 tomcat）之后才会发生这种崩溃。

ManagerBase 的这个无效实例从何而来？

嗯，不好说，但我猜它来自一个 ThreadLocal 变量，当你的应用程序被取消部署时没有正确清理。因此，您可以检查自己的代码，看看您是否没有滥用 ThreadLocal 变量（始终在您的请求过滤器中清理 finally 块中的所有 ThreadLocal 变量）。

如果您在自己的代码中没有找到任何内容：

仔细检查在您取消部署/部署网络应用程序时出现的所有日志（尤其是警告），您很有可能会发现“资源 X 无法释放”之类的内容。

关于您经常出现的 OutOfMemory 错误：它可能与此问题有关。实际上，如果在取消部署/部署应用程序时未正确清理某些 ThreadLocal 变量，则它是内存泄漏，因此最终可能导致 OutOfMemory。

我希望它有所帮助。（在取消部署/部署应用程序时发布日志可能很有趣。）

【讨论】：

【解决方案3】：

当重定向页面需要会话并且页面上下文设置机制 (PageContextImpl.java:146) 尝试创建会话时，实际上会出现异常。但是这次会话 id 生成器不知何故为空

    ManagerBase.java:807.....

     protected String generateSessionId() {

            String result = null;

            do {
                if (result != null) {                   
                    duplicates++;
                }

                result = sessionIdGenerator.generateSessionId();
//There is issue in the above line - sessionIdGenerator is null this time

            } while (sessions.containsKey(result));

            return result;
        }

此类间歇性发生的问题已报告here，对此问题有很多评论。看看有没有什么提示可以帮到你。

【讨论】：

能否请您看一下spring security配置，我认为这个异常是因为spring security。
您的配置似乎没问题。 redirect.jsp 是如何被调用的？我在 Tomcat 7 中使用 Spring 安全性已经很长时间了，不记得有这样的问题？
不是redirect.jsp，而是index.jsp。它的项目欢迎文件（web.xml）。我已经更新了堆栈跟踪。
当我尝试使用空指针异常访问索引页面时，我收到 index.jsp 的 500 错误，即使索引 jsp 存在于目录中。请检查更新的问题以获取详细信息。谢谢！
它是否存在于 /WEB-INF/jsp/index.jsp 中？