?struts2的jar包用的是2.5的

HTTP Status 404 - There is no Action mapped for namespace [/] and action name [HelloWorld_add_action] associated with context path [/HelloWorld].

HelloWorldAction.java

public?class?HelloWorldAction?extends?ActionSupport?{
?//?helloworld.action
?@Override
?public?String?execute()?throws?Exception?{??
??System.out.println("執(zhí)行Action");
??return?SUCCESS;
?}

?public?String?add()?{
??return?"add";
?}

?public?String?update()?{
??return?"update";
?}
}

struts.xml

<struts>
??<package?name="default"?namespace="/"?extends="struts-default">
?
??<action?name="*_*"?method="{2}"?class="com.imooc.action.{1}Action">
???<result?>/result.jsp</result>
???<result?name="add">/{2}.jsp</result>
???<result?name="update">/{2}.jsp</result>
??</action>
?</package>
?<constant?name="struts.enable.DynamicMethodInvocation"?value="false"></constant>
?
</struts>

?