java - 使用Tomcat 5.0配置Struts2.1.6时发生异常

我是Struts 2的新手。在使用Tomcat 5配置Struts 2时，收到以下异常。我搜索了很多论坛，但没有提供任何解决方案。

这是异常堆栈跟踪：

java.lang.NullPointerException
at com.opensymphony.xwork2.spring.SpringObjectFactory.getClassInstance(SpringObjectFactory.java:203)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyResultType(XmlConfigurationProvider.java:511)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addResultTypes(XmlConfigurationProvider.java:482)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:438)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:265)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:111)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:189)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:55)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:360)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:403)
at org.apache.struts2.dispatcher.FilterDispatcher.init(FilterDispatcher.java:190)

Here is my web.xml file:

    <?xml version="1.0" encoding="UTF-8"?>
    <web-app version="2.4"
        xmlns="http://java.sun.com/xml/ns/j2ee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
        http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
       <filter>
            <filter-name>struts</filter-name>
           <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
       </filter>
      <filter-mapping>
           <filter-name>struts</filter-name>
           <url-pattern>/*</url-pattern>
       </filter-mapping>
   </web-app>

这是struts.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
 <include file="struts-default.xml"/>
 <!-- Add packages here -->
 <package name="default" extends="struts-default">
  <action name="HelloWorld" class="com.sid.HelloWorldAction">
   <result>/pages/login.jsp</result>
  </action>
 </package>
</struts>

这是我在类路径上的jar列表：

commons-beanutils-1.7.0.jar
commons-collections-3.2.jar
commons-digester-1.8.jar
commons-fileupload-1.2.1.jar
commons-io-1.3.2.jar
commons-lang-2.4.jar
commons-logging-1.0.4.jar
commons-net-1.4.1.jar
commons-validator-1.3.0.jar
displaytag-1.1.jar
displaytag-export-poi-1.1.jar
freemarker-2.3.13.jar
ibatis-2.3.4.726.jar
iText-2.1.3.jar
jstl.jar
log4j-1.2.15.jar
邮件1.3.3.jar
ognl-2.6.11.jar
poi-3.0-rc4-20070503.jar
spring.jar
standard.jar
struts2-convention-plugin-2.1.6.jar
struts2-core-2.1.6.jar
struts2-spring-plugin-2.0.11.1.jar
struts2-tiles-plugin-2.1.6.jar
Tiles-api-2.0.6.jar
tiles-core-2.0.6.jar
Tiles-jsp-2.0.6.jar
xwork-2.1.2.jar

最佳答案

在使用spring插件时，尝试将Spring上下文加载器侦听器添加到web.xml中

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