背景
在实现了一个用户登录的拦截器后,判断session中是否存在用户的id,如果没有就跳转到登录界面,如果有就放行,发现这样对ajax请求没有作用,那么如何对ajax请求拦截后进行页面跳转呢?首先判断是否是ajax请求,如果是ajax请求就输出一个标志,然后再success中判断这个标志,然后根据标志在前端利用 window.location.href 进行页面的跳转
具体实现
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
HttpSession session = request.getSession();
Integer uid = (Integer) session.getAttribute("id");
String uri = request.getRequestURI();
if (uri.contains("login") || uri.contains("register")) {
return true;
}
if (uid == null) {
// 判断是否是ajax请求
String XRequested =request.getHeader("X-Requested-With");
if("XMLHttpRequest".equals(XRequested)) {
response.getWriter().write("FAILURE");
} else {
request.setAttribute("msg", "请登录后再操作");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
return false;
}
return true;
}
$.ajax({
url : "user/updateHeader",
type : "POST",
data : "base64=" + base64,
async : true,
success : function (msg) {
if (msg === "SUCCESS") {
alert("上传成功");
window.location.href = "index.jsp";
} else {
alert("上传失败,请登录后尝试");
window.location.href = "login.jsp";
}
}
})