• 在struts-default.xml中定义一个defaultStack拦截器栈，并将其指定为默认拦截器。
• 只要在定义包的过程中继承struts-default包，那么defaultStack将是默认的拦截器
• 当为包中的某个action显示指定了某个拦截器，则默认拦截器不会起作用
• 为action显示引用拦截器后，默认的拦截器defaultStack不再生效，需要手工引用
• 拦截器栈中的各个拦截器的顺序很重要

开发权限验证拦截器

    <h2>登录页面</h2>${loginError }<form action="login" method="post">用户名：<input type="text" name="username" /><br/>密码：<input type="password" name="password" /><br/><input type="submit" value="登录"/></form>

能获取session的action

package com.lijy.action;import java.util.Map;import org.apache.struts2.interceptor.SessionAware;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport implements SessionAware {private String username;private String password;private Map<String, Object> session;@Overridepublic void setSession(Map<String, Object> session) {this.session = session;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public Map<String, Object> getSession() {return session;}//处理登录请求public String login() {if ("admin".equals(username) && "123".equals(password)) {session.put("loginInfo", username);return SUCCESS;} else {session.put("loginError", "用户名或密码不正确！");return ERROR;}}}

给登录aciton添加过滤器

            <!-- 注册拦截器 --><interceptors><interceptor name="auth" class="com.lijy.interceptor.AuthInterceptor"></interceptor><!-- 自定义拦截器栈，组合了defaultStack和auth --><interceptor-stack name="myStack"><interceptor-ref name="defaultStack"></interceptor-ref><interceptor-ref name="auth"></interceptor-ref></interceptor-stack></interceptors><!-- 通过此Action访问后台管理页面,需要判断用户是否已登录，如果未登录则跳到登录页面 --><action name="auth"><result>/WEB-INF/page/manage.jsp</result><result name="login">/login.jsp</result><!-- 引用自定义拦截器栈 --><interceptor-ref name="myStack"></interceptor-ref></action>

             <action name="login" class="com.lijy.action.LoginAction" method="login">
             <result>/WEB-INF/page/manage.jsp</result>
             <result name="error">/login.jsp</result>
        </action>

拦截器

package com.lijy.interceptor;import java.util.Map;import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;public class AuthInterceptor extends AbstractInterceptor {@Overridepublic String intercept(ActionInvocation invocation) throws Exception {ActionContext context = ActionContext.getContext();Map<String, Object> session = context.getSession();if (session.get("loginInfo") != null) {String result = invocation.invoke();return result;} else {return "login";}}}