ajaxsetup,结合拦截器处理session过期，跳转登录页面

1.ajaxsetup------写在公用js中（每个ajax请求之后都会走这个回调）
2.拦截器设置回调的参数，或者请求状态，ajaxsetup回调参数做出处理
3、还可以自动将运行时异常，作为回调的参数（用于捕获异常，提示）
session过期，session=null，要跳转登录页面。跳出iframe,分ajax请求的跳转，普通连接的跳转(拦截处理response并不代表就中断请求返回，可以继续请求链，response继续传递)

package com.wondersgroup.employeeBenefits.core.author.util;

import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import com.wondersgroup.employeeBenefits.core.bases.model.User;
import com.wondersgroup.employeeBenefits.core.bases.util.SpringWebHolder;


public class HandlerSessionInterceptor extends HandlerInterceptorAdapter {//此处一般继承HandlerInterceptorAdapter适配器即可 
    @Override 
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { 
    request.setCharacterEncoding("UTF-8"); 
        response.setCharacterEncoding("UTF-8"); 
        response.setContentType("text/html;charset=UTF-8"); 
        HttpSession session= SpringWebHolder.getSession();
        User user = (User) session.getAttribute("LOGIN_USER");
        String uri = request.getRequestURI();
        uri.substring(0, uri.indexOf("/", 1));
        String[] notFilter = new String[] { "login", "validateCode", "index.do", "index.do", "index.do", "msg.do" ,"sendmail","mailcheck","sendSMS","assign","queryDictDataByParentId","eidtcode","eidtcodemail","saveusercode"};
        if (user==null)//判断session里是否有用户信息 
        { 
        boolean doFilter = true;
        for (String s : notFilter) {
                 if (uri.indexOf(s) != -1) {
                     // 如果uri中包含不过滤的uri，则不进行过滤
                     doFilter = false;
                     break;
               }
           }
        if(doFilter){
        if (request.getHeader("x-requested-with") != null 
                   && request.getHeader("x-requested-with") 
                       .equalsIgnoreCase("XMLHttpRequest"))//如果是ajax请求响应头会有，x-requested-with； 
        {
        response.setHeader("sessionstatus", "timeout");//在响应头设置session状态  
        response.setHeader("url", uri.substring(0, uri.indexOf("/", 1)));
       
        }else{
        PrintWriter out = response.getWriter(); 
                 StringBuilder builder = new StringBuilder(); 
                 builder.append("<script type=\"text/javascript\" charset=\"UTF-8\">"); 
                 builder.append("alert(\"页面过期，请重新登录\");"); 
                 builder.append("window.top.location.href=\""); 
                 builder.append(uri.substring(0, uri.indexOf("/", 1))+"/login.do"); 
                 builder.append("\";</script>"); 
                 out.print(builder.toString()); 
                 out.close(); 
        }
       
           return false; 
//         } 
//         response.setHeader("sessionstatus", "timeout");//在响应头设置session状态 
//         return false; 
       } 
        }
       return true; 
    } 
    @Override 
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { 
        System.out.println("===========HandlerInterceptor1 postHandle"); 
    } 
    @Override 
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { 
        System.out.println("===========HandlerInterceptor1 afterCompletion"); 
    } 
==========================
在公用的js中
/**
* 设置未来(全局)的AJAX请求默认选项
* 主要设置了AJAX请求遇到Session过期的情况
*/

$.ajaxSetup({
contentType:"application/x-www-form-urlencoded;charset=utf-8",
error: function (XMLHttpRequest, textStatus, errorThrown){
if(XMLHttpRequest.status==403){
alert('您没有权限访问此资源或进行此操作');
return false;
}
}, 
         complete:function(XMLHttpRequest,textStatus){  
        var sessionstatus=XMLHttpRequest.getResponseHeader("sessionstatus"); //通过XMLHttpRequest取得响应头,sessionstatus，
        var url=XMLHttpRequest.getResponseHeader("url");
                if(sessionstatus=='timeout'){  
                      //如果超时就处理 ，指定要跳转的页面 
             var top = getTopWinow(); //获取当前页面的顶层窗口对象
             alert('登录超时, 请重新登录.');
                 top.location.href=url+"/login.do"; //跳转到登陆页面
             }  
         }  
   });
/**
* 在页面中任何嵌套层次的窗口中获取顶层窗口
* @return 当前页面的顶层窗口对象------保证登出页面在最上窗口
*/
function getTopWinow(){
    var p = window;
    while(p != p.parent){
        p = p.parent;
    }
    return p;
}