---需求(摘自网络):
1."在一次做非常复杂的ajax应用时,如果一个会话已经超时,但是此时再通过ajax请求,那么ajax返回的则是一个登陆页面的html,那这下就惨了,页面上而已就乱了"
2."对于普通的http请求,可以通过过滤器Filter来判断session超时,然后跳转到登录页面;但是对于Ajax请求,则不会如期待的那样自动转到登录页面(我试了网站上的许多种方案,都是停留在当前页面)"
3.Ajax请求后台数据虽然会被过滤器filter拦截,但是因为Ajax操作与对页面整个页面的提交请求不一样,filter中的重定向并不能使之跳到一个新的页面,因此需要我们去做特殊的处理。处理原理很简单,如果session超时,filter返回一个超时标识给客户端,客户端检测到超时头信息,跳转到指定页面。
4.当session超时时,如果不是ajax请求,很简单就能实现跳到指定的页面;但是ajax请求就会有问题:如果是ajax类型的弹出框则会在弹出框中显示跳转的指定页面,如果是正常ajax请求,则可能会显示源代码等。
5.http://www.iteye.com/topic/1126552
6.http://www.cnblogs.com/shencheng/archive/2011/01/07/1930227.html
7.区分ajax请求和普通http请求:session超时处理、exception处理
---sessionListener
web.xml:
<session-config> <session-timeout>1</session-timeout> <!--单位min,若为-1则永远不超时--> </session-config> <listener> <listener-class>test.MyHttpSessionListener</listener-class> </listener>
Listener:
public class MyHttpSessionListener implements HttpSessionListener { //创建 public void sessionCreated(HttpSessionEvent arg0) { System.out.println("sessionCreated.........."); } //销毁 public void sessionDestroyed(HttpSessionEvent arg0) { System.out.println("sessionDestroyed........"); } }
---session过期判断:跳转到登录页面
web.xml:(配置在springmvc的拦截之前)
<filter> <filter-name>sessionFilter</filter-name> <filter-class>test.SessionFilter</filter-class> </filter> <filter-mapping> <filter-name>sessionFilter</filter-name> <url-pattern>/user/*</url-pattern> </filter-mapping>
Filter:
public class SessionFilter implements Filter { public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { if (!(request instanceof HttpServletRequest) || !(response instanceof HttpServletResponse)) { throw new ServletException("OncePerRequestFilter just supports HTTP requests"); } HttpServletRequest req = (HttpServletRequest) request; HttpServletResponse res = (HttpServletResponse) response; // String userId = (String) req.getSession().getAttribute("userId"); // if ((userId == null) || "".equals(userId)) { // res.sendRedirect(req.getContextPath() + "/loginDemo"); // } System.out.println("判断: " + req.getSession(false)); if (null == req.getSession(false)) { // if (true == req.getSession(true).isNew()) { // System.out.println("new request"); // } System.out.println("session已经过期"); if (req.getHeader("x-requested-with") != null && req.getHeader("x-requested-with").equalsIgnoreCase("XMLHttpRequest")) { System.out.println("ajax超时处理.............."); res.addHeader("sessionstatus", "timeout"); res.addHeader("loginPath","loginurl"); res.setCharacterEncoding("utf-8"); res.setContentType("text/html;charset=UTF-8"); OutputStream out = response.getOutputStream(); PrintWriter pw = new PrintWriter(new OutputStreamWriter(out,"utf-8")); pw.println("{\"result\":false,\"errorMessage\":\"您未登录,请先登录\"}"); pw.flush(); pw.close(); //前端js处理 return; }else{ System.out.println("http超时处理............."); res.sendRedirect(req.getContextPath() + "/index.page"); return; } } else{ System.out.println("Session is active!"); } System.out.println("sessionFilter doFilter.........."); chain.doFilter(request, response); } public void destroy() { } public void init(FilterConfig filterConfig) { } }
--前端JS处理:
$(document).ajaxComplete(function(event, xhr, settings) { if(xhr.getResponseHeader("sessionstatus")=="timeOut"){ if(xhr.getResponseHeader("loginPath")){ window.location.replace(xhr.getResponseHeader("loginPath")); }else{ alert("Request time out relogin plase !"); } } }); //全局的ajax访问,处理ajax清求时sesion超时 $.ajaxSetup({ contentType:"application/x-www-form-urlencoded;charset=utf-8", complete:function(XMLHttpRequest,textStatus){ //通过XMLHttpRequest取得响应头,sessionstatus, var sessionstatus=XMLHttpRequest.getResponseHeader("sessionstatus"); if(sessionstatus=="timeout"){ //如果超时就处理 ,指定要跳转的页面 window.location = "<c:url value="/" />"; } } });