核心方法:

HttpServletRequest response.sendRedirect(url)

举个例子
项目需求:在一个页面中点击下载按钮会去访问后端一个接口然后下载文件,当登录超时失效时,点击下载按钮进行跳转登录页.
解决方法:

    
    @ApiOperation(value = "导出Word")
    @ApiImplicitParam(name = "anhao", value = "案号", required = true)
    @GetMapping("/createWord")
    public Response createWord(HttpServletResponse response, HttpServletRequest request, @RequestParam("anhao") String anhao) throws IOException{
        Object mapObject = MemoryCache.get(anhao);//如果登录超时,就获取不到缓存了,就会为空.
        if (mapObject == null) {
       		String referer = request.getHeader("Referer");//这是获取点击下载按钮的那个页面的URL
            response.sendRedirect(referer);
            //上面再次访问点击按钮那个页面,如果登录超时就会跳转到登录页,也可以通过请求头拿到项目的IP,端口再拼接上登录的字段URL直接跳转到登录页.
            return null;
        }else {
		//这里省略下载文件的逻辑
        }
    }