问题描述：
The Struts dispatcher cannot be found. This is usually caused by using Struts tags without the associated filter. Strut s tags are only usable when the request has passed through its servlet filter, which initializes the Struts dispatcher needed for this tag. - [unknown location]
操作：struts2中直接访问jsp
异常：The Struts dispatcher cannot be found. This is usually caused by using Struts tags without the associated filter. Struts tags are only usable when the request has passed through its servlet filter, which initializes the Struts dispatcher needed for this tag.
环境:struts2
原因：如果想要在jsp文件中，采用 struts的tag，那么jsp必须是通过action跳转得到，也就是必须通过web.xml所配置的过滤器访问文件，否则会有异常。
解决办法：
方案一：将web.xml 的过滤器，从 *.action 修改为： /* 。
方案二：web.xml 中添加一个filter
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/action/*</url-pattern>
</filter-mapping>
方案三：web.xml中加一段
<jsp-config>
<taglib>
<taglib-uri>struts-tags</taglib-uri>
<taglib-location>/WEB-INF/struts2－core－2.0.11.jar/struts-2.0.dtd</taglib-location>
</taglib>
</jsp-config>
方案四：采用action访问jsp页面。
方案五：修改jsp页面，不使用struts标签。