struts2 拦截器配置

CheckLoginInterceptor.java---拦截器具体实现类： 

package com.sunhoo.hcpms.struts2.action.interceptors;

import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
import com.sunhoo.hcpms.struts2.action.LoginAction;

/**
 * 拦截器 拦截没有登录的用户
 *
 * @author lyvee AbstractInterceptor 抽象类
 */
public class CheckLoginInterceptor extends AbstractInterceptor {
    public static ActionContext ctx;
    public static Map sessionMap = null;
    String task = "userLogin";

    @Override
    public String intercept(ActionInvocation actionInvocation) throws Exception {
        ctx = actionInvocation.getInvocationContext();
        sessionMap = actionInvocation.getInvocationContext().getSession();
        HttpServletRequest request = (HttpServletRequest) ctx
                .get(ServletActionContext.HTTP_REQUEST);
        String user_session_key = "currentUser";// 默认的key
        System.out.println("begin check login interceptor");
        // not to intercepted on loginAction
        Object action = actionInvocation.getAction();
        if (action instanceof LoginAction) {
            System.out.println("exit check login,because this is loginAction");
            actionInvocation.invoke();
            return null;
        } else {
            String returnStr = "logout";

            if (null == request.getParameter("task") || "".equals(task)) {//如果task为空 则等于userLogin
                task = "userLogin";
            }else {
                task = request.getParameter("task");
            }if (task.equals("userLogin")) {// 根据不同的登录类型赋予user_session_key不同的value
                user_session_key = "currentUser";
            } else if (task.equals("expertLogin")) {
                user_session_key = "currentExpert";
                returnStr="expertlogout";
            } else if (task.equals("adminLogin")) {
                user_session_key = "currentAdmin";
                returnStr="adminLogout";
            }
            // check session
            @SuppressWarnings("unused")
            Object okk = sessionMap.get(user_session_key);
            String userName = (String) sessionMap.get(user_session_key);
            // if userName already login
            if (userName != null) {
                System.out.println("already login!");
                actionInvocation.invoke();
            } else {// no login
                System.out.println("no login.forward login page");
                return returnStr;
            }
        }
        return null;
    }

}

struts.xml配置： 

<package name="default" namespace="/" extends="struts-default">
<!-- 定义一个名为 checkLogin 的拦截器 -->
<interceptors>
    <!-- 定义权限检查拦截器 类级别-->
    <interceptor name="checkLogin"
        class="com.sunhoo.hcpms.struts2.action.interceptors.CheckLoginInterceptor" />
        <!-- 定义一个权限检查的拦截器 方法级别 -->
    <interceptor name="methodInterceptor" class="com.sunhoo.hcpms.struts2.action.interceptors.MethodInterceptor">
        <param name="excludeMethods"></param>
        <param name="includeMethods">expertTree</param>
    </interceptor>
    <!-- 定义一个包含权限检查的拦截器栈 -->
    <interceptor-stack name="myDefaultStack">
        <!-- 定义拦截器栈包含checkLogin拦截器 -->
        <interceptor-ref name="checkLogin"></interceptor-ref>
        <interceptor-ref name="defaultStack"></interceptor-ref>
        <interceptor-ref name="methodInterceptor"></interceptor-ref>
    </interceptor-stack>
</interceptors>
<!-- 设置全局 全局默认的拦截器栈-->
<default-interceptor-ref name="myDefaultStack"></default-interceptor-ref>

<global-results>
    <result name="logout" type="dispatcher">/login.jsp</result>
    <result name="succ">/client/succ.jsp</result>
    <result name="fail">/client/fail.jsp</result>
    <result name="expertlogout" type="redirect">/expert/login.jsp?errorMsg=${errorMsg}</result>
    <result name="adminLogout" type="redirect"></result>
</global-results>
<action name="login_*" class="LoginAction" method="{1}">
    <result name="index" type="redirect">
        /question_questionList?task=userLogin
    </result>
    <result name="expertQuestions" type="redirect">
        /expert_queryQuestions?task=expertLogin
    </result>
    <result name="go" type="redirect">
        expertList.jsp
    </result>
    <interceptor-ref name="myDefaultStack" />
</action>
<action name="register_*" class="RegisterAction" method="{1}">
    <interceptor-ref name="methodInterceptor" />
</action>
<action name="expert_*" class="ExpertAction" method="{1}">
    <result name="index">
        /expert/questionList.jsp?task=expertLogin
    </result>
    <result name="expertView">/client/expertList.jsp?task=expertLogin</result>
</action>.............................

        以上就是我的拦截器配置 
         我遇到的问题是  现在有三种不同类型的用户需要验证登录 1.专家 2.会员 3.专家。通过

task = request.getParameter("task");

来判断登录用户的类型 然后取得不同的session值来进行拦截。  我不知道这种方法行不行。不是说其他的行不行 因为我已经实现了 并且成功进行了三种不同类型的用户登录来拦截 反正就是我心里觉得这么做不对，不知道JE上有没有人做过类似的 请问你们怎么做的。