namespace老师报错

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
    "http://struts.apache.org/dtds/struts-2.1.7.dtd">

<struts>
	<include file="struts-default.xml" />
	<package name="admin" extends="struts-default" namespace="admin">
		<action name="login" class="com.lfq.action.UserAction" method="login">
			<result name="input">/admin/login.jsp</result>
			<result name="success">/admin/index.jsp</result>
		</action>
	</package>
</struts>

老是报找不到action的错误，检查了半天，才明白，namespace="/admin"

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
    "http://struts.apache.org/dtds/struts-2.1.7.dtd">

<struts>
	<include file="struts-default.xml" />
	<package name="admin" extends="struts-default" namespace="/admin">
		<action name="login" class="com.lfq.action.UserAction" method="login">
			<result name="input">/admin/login.jsp</result>
			<result name="success">/admin/index.jsp</result>
		</action>
	</package>
</struts>

并且在admin目录里的登录表<s:form> 的namespace是不用写的