The content of element type "struts" must match "((package|include|bean|constant)*,unknown-handler-s

<struts>

<!-- 配置为开发模式 -->

    <constant name="struts.devMode" value="true" />

<!-- 扩展名配置为action -->

<content
name="struts.action.extension" value="action"/>

    <!-- 把主题配置simple -->

    <content name="struts.ui.theme" value="simple"/>





    <!-- Add packages here -->

</struts>

以上提示了：The content of element type "struts" must match "((package|include|bean|constant)*,unknown-handler-s

在配置struts.xml文件时不小心把红色部分的字写错了，应改为constant