登陸：
dao: criteria.add(Restrictions.eq("name"， name));
service:
User u = dao.get(user.getName)
if(u==null)
拋出不存在用戶名異常
if(!user.getPwd.eq(u.getPwd))
拋出不存在密碼異常
return u;
interceptors:
1.自定攔截器LoginInterceptor extends MethodFilterInterceptor
2.return "toLogin"；
action:
User u = service.get(user);
return "toindex"http://重定向避免表單重復提交..
struts.xml:

1. <interceptors>
   <interceptor name="loginInterceptor" class> </interceptor>
   < interceptor-stack name="myStack">
   <interceptor-ref name="loginInterceptor" >
   <param name="excludeMethods">login, regist</param>
   </interceptor-ref>
   <interceptor-ref name="defaultStack"></interceptor-ref>
   </interceptor-stack>
   </interceptors>
   <def-interceptor-ref name=""></def-interceptor-ref>
2. <gloabl-result>
   <result name="toLogin"></result>
   </gloabl-result>
   3.<gloabl-exception-mappings>
   <exception-mapping result="error" class="java.lang.RunntimeException">
   </exception-mapping>
   </gloabl-exception-mappings>
   <action name="UserAction_*" method={1} class="...">
   <result name="toindex" type="redirectAction">page_index</result>
   <result name="error">/login.jsp</result>
   </action>
   4.隱藏靜態資源至WEB-INF中： <action name="page_*">
   <result >/WEB-INF/page_{1}</result>
   </action>
   頁面需從valueStack中接收exception.message：
   <s:property value="exception.message">