两部曲:
1:在你的web.xml中的Struts2的核心过滤器的映射中添加
<filter-mapping>
    <dispatcher>REQUEST</dispatcher>
    <dispatcher>FORWARD</dispatcher>
    <filter-name>struts2</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

2:把welcomelist改成你查询的action


<meta http-equiv='refresh' content='0;url=show.action'>