运行Spring项目时出现空指针异常

Question

我无法在Spring项目中找出NullPointer异常的原因。有时候项目工作正常，但有时候它抛出空指针异常就是完全堆栈跟踪。

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)

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

-XX:MaxPermSize=512m

我使用的是Netbeans IDE 7.3.1，Apache Tomcat 7.0.37，Spring 3.1.1，Hibernate 3.

它在Exception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!

我目录中的index.jsp。 我是否需要在/ index？

的spring security intercept url标签中定义映射

Answer 1

问题的根本原因是tomcat ManagerBase中的null sessionIdGenerator。

快速查看code：可能只有Manager尚未启动，或者它已经停止。我的猜测是你的代码正在使用“已经停止”的经理。

如果我错了，请纠正我，但我猜你在取消部署/部署应用程序之后只会发生此崩溃（不完全重启tomcat）。

ManagerBase的这个无效实例来自哪里？

嗯，不容易说，但我猜它来自一个ThreadLocal变量，当你的应用程序被取消部署时，它没有被正确清理。 因此，您可以检查自己的代码，看看您是否没有滥用ThreadLocal变量（始终清理请求过滤器中finally块中的所有ThreadLocal变量。）

如果您在自己的代码中找不到任何内容：

仔细检查取消部署/部署Web应用程序时发生的所有日志（尤其是警告），您很可能会发现“资源X无法释放”等内容。

关于您的周期性OutOfMemory错误：它可以链接到此问题。实际上，如果在取消部署/部署应用程序时某些ThreadLocal变量未正确清理，则会导致内存泄漏，因此最终会导致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。）

Answer 2

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，实际发生异常。然而，这次会话id生成器以某种方式为空

    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;
        }

这种间歇性发生的问题已被报告here，并且对此问题有很多评论。 看看是否有一些可以帮助你的提示。

Answer 3

您是否在jsp的应用程序上下文中配置了视图解析程序？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。 如果上面的内容正确执行，则应该使用spring security配置。