struts2 过滤器学习

<struts>
    <constant name="struts.devMode" value="true" /><!-- 开发者模式-->
    <constant name="struts.multipart.maxSize" value="50000000" /><!--设置最大上传限制，默认不超过2m（具体不清楚）-->
    <package name="test" extends="struts-default" namespace="/">
        
             <!-- 定义一个拦截器 -->  
        <interceptors>  
            <interceptor name="authority"    class="com.zzbj.util.LoginInterceptor">  
            </interceptor>  
            <!-- 拦截器栈 -->  
            <interceptor-stack name="mydefault">  
                <interceptor-ref name="defaultStack" /> 
                <interceptor-ref name="authority" />  
            </interceptor-stack>  
        </interceptors>        
        <default-interceptor-ref name="mydefault"/> <!--定义为默认拦截器，全局拦截，也可以针对action 定义拦截器-->      
        <!-- 定义全局Result -->  
        <global-results>  
            <!-- 当返回login视图名时，转入/login.jsp页面 -->  
            <result name="login">/index.jsp</result>  
          <!--后面三个是捕获action throws Exception-->
            <result name="sql">/Error.jsp</result>
            <result name="invalidinput">/Error.jsp</result>
            <result name="naming">/Error.jsp</result>
        </global-results>
        <global-exception-mappings>
            <exception-mapping result="sql" exception="java.sql.SQLException"></exception-mapping>
            <exception-mapping result="invalidinput"
                exception="cn.codeplus.exception.InvalidInputException"></exception-mapping>
            <exception-mapping result="naming"
            exception="javax.naming.NamingException"></exception-mapping>
        </global-exception-mappings>        
        <action name="user_*" class="com.zzbj.action.UserAction"
            method="{1}">
            <result>/UserManage.jsp</result>
        </action>
    </package>
</struts> 

 1 public class LoginInterceptor extends AbstractInterceptor {   
 2     @Override  
 3     public String intercept(ActionInvocation invocation) throws Exception {  
 4         System.out.println("映射");
 5         // 取得请求相关的ActionContext实例  
 6         ActionContext ctx = invocation.getInvocationContext();  
 7         Map session = ctx.getSession();  
 8         String userRule = (String) session.get("RULE");  
 9         // 如果没有登陆，或者权限rule首位不为1（没有该类权限），都返回重新登陆  
10         if (userRule != null && userRule.charAt(0)==‘1‘) {  
11             System.out.println("已登录");  
12             return invocation.invoke();  
13         }  
14         ctx.put("return", "你还没有登录");  
15         return Action.LOGIN;  
16     }    
17 }