ajax异步请求，session失效处理

后台拦截器代码：

// 判断是否是AJAX请求
if (isAjaxRequest(request)) {
    log.info("AjaxRequest请求");
    ActionContext ac = arg0.getInvocationContext();
    HttpServletResponse response = (HttpServletResponse)ac.get(StrutsStatics.HTTP_RESPONSE);
    response.setHeader("sessionstatus", "timeout");//返回前台的标志
    //response.sendError(518, "session timeout.");//5**，表示服务器错误

    return null;
}

/**
* 判断是否是ajax请求
* @param request
* @return
*/
private boolean isAjaxRequest(HttpServletRequest request) {
    String header = request.getHeader("X-Requested-With");
    if (header != null && "XMLHttpRequest".equals(header)) {
        return true;
    } else {
         return false;
    }
}

　　

/**

* =============js代码===================================
* 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
*/

var flag = true;//防止重复点击
var domain = document.domain;
var ip = /^(\d+)\.(\d+)\.(\d+)\.(\d+)$/;
var path = (ip.test(domain))?("http://"+domain+":8081/WSS"):("http://"+document.domain);
console.log(path);
$.ajaxSetup({
    type: 'POST',
    complete: function(xhr,status) {
        var sessionStatus = xhr.getResponseHeader('sessionstatus');
        if(sessionStatus == 'timeout' && flag ) {
            flag = false;
            var top = getTopWinow();
            $.TipsBox.Alert("由于您长时间没有操作, session已过期, 请重新登录","error","",function(){
                //成功回调
                flag = true;
                top.location.href = path+"/sys/login.htm";
            });
        }
    }
});
/**
* 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
*/
function getTopWinow(){
    var p = window;
    while(p != p.parent){
        p = p.parent;
    }
    return p;
}

　　

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$.ajaxSetup详解，参数另见 ‘$.ajax’