springboot shiro实现登录跳转原先页面

在项目的会遇到请求后台页面会出现未登录跳转到登录页面,登录完成后再跳转回登录页面,又于项目登录是采用ajax编写的,只需在登录成功后将需要跳转的页面返回就可以.
后台登录控制器

@PostMapping(value = {"/admin/login"})
    @ResponseBody
    public LayResponse login(@RequestParam Map<String, String> param, HttpServletRequest req) {
        //用户认证信息
        Subject subject = SecurityUtils.getSubject();
        UsernamePasswordToken usernamePasswordToken = new UsernamePasswordToken(param.get("username"), param.get("password"));
        LayResponse response = new LayResponse();
        response.success("登录成功");
        try {
            //进行验证，这里可以捕获异常，然后返回对应信息
            subject.login(usernamePasswordToken);
            SavedRequest savedRequest= WebUtils.getSavedRequest(req);//将需要调整的页面传回前段,前段进行跳转
            response.data(savedRequest);
        } catch (UnknownAccountException e) {
            response.error("用户名不存在！");
        } catch (AuthenticationException e) {
            response.error("账号或密码错误！");
        } catch (AuthorizationException e) {
            response.error("没有权限");
        } catch (Exception e) {
            response.error("其他错误");
        }
        return response;
    }

前台layui登录

//监听提交
            form.on('submit(login)', function (data) {
                $.post("/admin/login", data.field, function (res) {
                    if (res.code == 0) {
                        if(res.data!=null){
                            if(res.data.method=='GET'){
                                location.href =res.data.requestUrl;
                                return false;
                            }
                        }
                        location.href = '/admin/index/index'
                    } else {
                        layer.msg(res.msg, {icon: 5});
                    }
                });
                return false;
            });

登录成功返回的json