自定义拦截器

package com.cn.interceptors;

import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.cn.domain.User;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.MethodFilterInterceptor;
//执行动作方法前检查用户是否已经登录
public class SessionCheckInterceptors extends MethodFilterInterceptor{

    @Override
    protected String doIntercept(ActionInvocation invocation) throws Exception {
        String result = "login";//对应的就是一个结果（即action的结果配置：<result name="login">/login.jsp</result>）
        HttpSession session = ServletActionContext.getRequest().getSession();
        User user = (User)session.getAttribute("user");
        if(user!=null)
            result = invocation.invoke();
        return result;
    }
    
}

在Struts配置文件中进行配置：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>
    <constant name="struts.devMode" value="true"></constant>
    
    <package name="mypackage" extends="struts-default" abstract="true">
        <interceptors>
            <interceptor name="sessionCheck" class="com.cn.interceptors.SessionCheckInterceptors">
                <!-- 说明test2动作方法不需要拦截（这里是指action的method方法） -->
                <param name="excludeMethods">test2</param>
            </interceptor>
            <interceptor-stack name="myDefaultStack">
                <interceptor-ref name="defaultStack"></interceptor-ref>
                <interceptor-ref name="sessionCheck"></interceptor-ref>
            </interceptor-stack>
        </interceptors>
        <default-interceptor-ref name="myDefaultStack"></default-interceptor-ref>
    </package>
    
    <package name="p1" extends="mypackage">
        <action name="test1" class="com.cn.action.HelloAction1" method="test1">
            <result>/1.jsp</result>
            <result name="login">/login.jsp</result>
        </action>
        <action name="test2" class="com.cn.action.HelloAction1" method="test2">
            <result>/2.jsp</result>
        </action>
    </package>
</struts>