在Struts應用中，我們發出的請求都會經過 相應的攔截器進行相關處理，一般都會有一個用戶登錄攔截（Session失效攔截）；一般請求的話，如果Session失效時，我們會跳到登錄頁面，可是如果我們采用AJAX請求時，將會返回登錄頁面的HTML代碼，這肯定不是我們想要的，那么我們如何解決呢？請看以下步驟：

一、建立攔截器

package com.xxx.planeap.interceptor;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.log4j.Logger;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.ActionSupport;import com.opensymphony.xwork2.interceptor.AbstractInterceptor;import com.xxx.common.contants.ConstantsKey;import com.xxx.common.contants.SessionKey;import com.xxx.planeap.domain.User;import com.xxx.planeap.security.SecurityContextUtil;/*** * @author Goma OMA1989@YEAH.NET* @version v1.0* @since 2012-05-31* */public class SecurityInterceptor extends AbstractInterceptor {private static final long serialVersionUID = 1L;private Logger logger = Logger.getLogger(SecurityInterceptor.class);@Overridepublic String intercept(ActionInvocation invocation) throws Exception {// TODO Auto-generated method stubString className = invocation.getAction().getClass().getName();String action = className.substring(className.lastIndexOf(".")+1,className.length());String actionName = invocation.getProxy().getActionName();String result;HttpServletRequest request = ServletActionContext.getRequest();HttpServletResponse response = ServletActionContext.getResponse();String type = request.getHeader("X-Requested-With");User user = (User) ActionContext.getContext().getSession().get(SessionKey.CURRENT_USER);if (user == null) {logger.debug("SECURITY CHECKED: NEED TO LOGIN");if ("XMLHttpRequest".equalsIgnoreCase(type)) {// AJAX REQUEST PROCESSresponse.setHeader("sessionstatus", ConstantsKey.MSG_TIME_OUT);result = null;} else {// NORMAL REQUEST PROCESSresult = ActionSupport.LOGIN;}} else {logger.debug("SECURITY CHECKED: USER HAS LOGINED");SecurityContextUtil.setCurrentUser(user);boolean hanPerm = SecurityContextUtil.hasPerm(action, actionName);logger.debug("SECURITY CHECKED: PERMISSION---"+action+"."+actionName+"="+hanPerm);result = invocation.invoke();}return result;}}

二、定義全局AJAX請求結束處理方法

//全局的AJAX訪問，處理AJAX清求時SESSION超時$.ajaxSetup({contentType:"application/x-www-form-urlencoded;charset=utf-8",complete:function(XMLHttpRequest,textStatus){//通過XMLHttpRequest取得響應頭，sessionstatus var sessionstatus=XMLHttpRequest.getResponseHeader("sessionstatus"); if(sessionstatus=="timeout"){//這里怎么處理在你，這里跳轉的登錄頁面window.location.replace(PlanEap.getActionURI("login"));}}});

也就是ajax發送請求時如果攔截返回一個表示就跳轉，否則執行正常操作。