struts2 拦截器

package intercepter;

import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;
//自定义拦截器   
/*
  继承Interceptor 这个类
  重写public string intercept（......）方法
*/
public class PermissionIntercepter implements Interceptor {

public void destroy() {
// TODO Auto-generated method stub

}

public void init() {
// TODO Auto-generated method stub

}

public String intercept(ActionInvocation invocation) throws Exception {
// TODO Auto-generated method stub
         Object user =ActionContext.getContext().getSession().get("user");
if(user!=null) return invocation.invoke();

ActionContext.getContext().getSession().put("message", "用户登录失败");
return "success";
}

}



/*
action 注册拦截器
<interceptor name="permission" class="intercepter.PermissionIntercepter"/>
添加单个的
<default-interceptor-ref name="permission"></default-interceptor-ref>
一般做法是添加一个拦截器栈
   <interceptor-stack name="permissionStack"> 
                   <interceptor-ref name="defaultStack"></interceptor-ref> 
                   <interceptor-ref name="permission"></interceptor-ref> 
   </interceptor-stack>
在吧拦截器栈添加给某个action  或者添加给某个包
*/

<struts>
   <package name="5aaa" namespace="/5aaa" extends="struts-default" >
    
     <interceptors> 
             <interceptor name="permission" class="intercepter.PermissionIntercepter"/>
             <interceptor-stack name="permissionStack"> 
                   <interceptor-ref name="defaultStack"></interceptor-ref> 
                   <interceptor-ref name="permission"></interceptor-ref> 
            </interceptor-stack>
     </interceptors>
     <default-interceptor-ref name="permission"></default-interceptor-ref>
    
   
      <global-results>
        <result name="success">/WEB-INF/page/2.jsp</result>
     </global-results>
     
      <action name="aaa" class="sss.Fifth" method="execute">
      </action>
   </package>
  
 
</struts>