java web exports data as code snippets in pdf format files

What this snippet does: upon accessing the request, the browser opens a new screen and displays the pdf file preview, which can be downloaded from the file preview screen.

1. jsp interface code

< input type="button" class="btn btn-info "onclick="getVerPdf();" target="_blank" value=" export as pdf file "/ >

2. js code

function getVerPdf() {
 window.open('/pms/jsp/version/getPrdVerListPdf?page='
   + $("#getPage").html() + '&key=' + $("#select").val());
}

3. java code

/**
  * 
  * Purpose : Export the product version list as pdf format 
  * 
  * @param req
  *    request 
  * @param resp
  *    The reply 
  * @param page
  *    The current number of pages 
  */
 @RequestMapping(value = "getPrdVerListPdf")
 public void getPrdTypeList(HttpServletRequest req, HttpServletResponse resp, Integer page, String key) {
  resp.setContentType("application/pdf");
  //  Select save path and file name 
  // resp.setHeader("content-disposition",
  // "attachment;filename=PrdVerList.pdf");

  //  Get the data for the current page 
  List<Version> verList = prdVersionSer.getAllPrdVersion(key);
  if (verList.size() == 0) {
   //  If there is no data, it returns to the main screen and displays a prompt message 
   req.setAttribute("getFileMsg", " No qualified information! ");
   req.setAttribute("select", key);
   try {
    req.getRequestDispatcher("/jsp/version/ver_list.jsp").forward(req, resp);
   } catch (Exception e) {
    e.printStackTrace();
   }
  } else {
   //  If there is data, display pdf file 
   JRBeanCollectionDataSource ds = new JRBeanCollectionDataSource(verList);
   String reportPath = null;
   Map<String, Object> map = new HashMap<String, Object>();
   if (key != "") {
    map.put("prdName", verList.get(0).getPrdName());
   } else {
    map.put("prdName", "");
   }
   reportPath = req.getServletContext().getRealPath("/reports/prdVerListByPrdName.jasper");
   InputStream is = null;

   try {
    is = new FileInputStream(reportPath);
    JasperRunManager.runReportToPdfStream(is, resp.getOutputStream(), map, ds);
   } catch (Exception e) {
    e.printStackTrace();
   } finally {
    if (is != null) {
     try {
      is.close();
     } catch (IOException e) {
      e.printStackTrace();
     }
    }
   }
  }
 }