如何解决Struts2程序报错：java.lang.ClassCastException

具体错误如下：

严重: Allocate exception for servlet struts2
java.lang.ClassCastException: org.apache.struts2.dispatcher.FilterDispatcher cannot be cast to javax.servlet.Servlet

at java.lang.Thread.run(Thread.java:619)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:827)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:129)
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:103)
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.Http11AprProcessor.process(Http11AprProcessor.java:879)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:617)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1760)
at java.lang.Thread.run(Thread.java:619)

web.xml 配置如下：

<servlet>
    <servlet-name>struts2</servlet-name>
    <servlet-class>org.apache.struts2.dispatcher.FilterDispatcher</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>struts2</servlet-name>
    <url-pattern>/*</url-pattern>
</servlet-mapping>

解决方法：
web.xml配置struts2拦截器，不能使用<servlet></servlet>标签，应该使用<filter></filter>标签配置，如下：

<filter>
    <filter-name>struts2</filter-name>
    <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>
<filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

程序能正常访问，问题解决！