springmvc 拦截器区分ajax请求

引子

ajax代码

[code]$(document).ready(function(){
    $(".new_bt").click(function(){
        data = ...;
        $.ajax({
            type: "POST",
            url: "../index/saveYue.do",
            data:data,
            dataType: "json",
            success:function(data){
                //成功的处理
            }
            error:function(data){   
                if(data.responseText=='loseSession'){
                    //session失效时的处理  
                }
            }
        });
    });

拦截器代码

[code]    @Override
    public boolean preHandle(HttpServletRequest req, HttpServletResponse resp, Object obj){     
        //一系列处理后发现session已经失效
        if (req.getHeader("x-requested-with") != null && req.getHeader("x-requested-with").equalsIgnoreCase("XMLHttpRequest")){ //如果是ajax请求响应头会有x-requested-with  
            PrintWriter out = resp.getWriter();  
            out.print("loseSession");//session失效
            out.flush();
            return false;
        }else{
            //非ajax请求时，session失效的处理
        }
        return true;
    }