@PostMapping(value = "getReport")
public void getReport(@RequestBody MainRequest<WebReportRequestDTO> request, HttpServletResponse res) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException, IOException {
        WebReportRequestDTO req = request.getRequest();
        File file = webReportService.createReportView(req.getReportParams());
        String content = new String(Files.readAllBytes(file.toPath()));
        res.setContentType("text/html");
        res.setCharacterEncoding("UTF-8");
        OutputStream out = res.getOutputStream();
        out.write(content.getBytes("UTF-8"));
        out.flush();
        out.close();
}

public File createReportView(WebReportParamsDTO params, String templateName) throws JRException, ParseException, IOException {
        // Здесь идет параметров и данных для отчета
        ...
        JasperPrint print = JasperFillManager.fillReport(jasperReport, reportParams, beanColDataSource);

        String fileName = templateName + String.valueOf(new Date().getTime());

        JasperExportManager.exportReportToHtmlFile(print, "c:/" + fileName + ".html");
        File file = new File("c:/" + fileName + ".html");
        return file;
    }