Angular请求后端Sping Boot Application生成Excel的界面，出现跨域错误，但是我已经在后端做了跨域处理，这是怎么回事？
Access to XMLHttpRequest at 'http://localhost:8080/api/ticket/myTicketDownload' from origin 'http://localhost:4200' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

@CrossOrigin
    @GetMapping("/ticket/myTicketDownload")
    public void myTicketDownload(HttpServletResponse response ) throws IOException {
        response.reset();
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        String day = DateUtils.localDateformat(LocalDate.now());
        String fileName = URLEncoder.encode("myTicket"+day, "UTF-8").replaceAll("\\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
        TicketQueryDto ticketQueryDto = new TicketQueryDto();
        ticketQueryDto.setPkMyTicket("111");
        List<TicketVo> allTicketData = iTicketGeneralService.getMyTicketData(ticketQueryDto);
        EasyExcel.write(response.getOutputStream(), TicketVo.class).sheet(day).doWrite(allTicketData);

    }

//Angular 
ExportMyTicket(){
    return this.http.get<void>(`http://localhost:8080/api/ticket/myTicketDownload`)
    }