Not able to get getOutputStream() working in servlet

Question

I am sending a json object to servlet and calling servlet through a function. Here is my jsp page and function:

    <script type="text/javascript">
function retrieveTicketsExcel(){
    var jsonData = {};
    jsonData["tower"]=$('#appTower').val();
    jsonData["sDate"]=$('#startDate').val();
    jsonData["eDate"]=$('#endDate').val();
    jsonData["apps"]=$('#appfilter').html();
    jsonData["duration"]=$('#duration').val();
    jsonData["severity"]=$('#severity').val();
    jsonData["releasetype"]=$('#releasetype').val();
    jsonData["query"]=$('#query').val();

         $.ajax
            ({
                type: "GET",
                url:"retrieveTicketsToExcel.htm",
                data:'requestData='+JSON.stringify(jsonData),
                dataType: "json",

            });
         }
</script>
    <div class="modal-footer">
              <input type="button" class="btn btn-default" value="Export" onclick="javascript:retrieveTicketsExcel();">
              <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
            </div>

Now i am calling Servlet method which is:

@RequestMapping(value = "/retrieveTicketsToExcel.htm", method = RequestMethod.GET)
public void retrieveTickets(@RequestParam("requestData") String requestData, HttpServletRequest request, HttpServletResponse response) throws IOException {
    // UserDAO userDAO = new UserDAO();
    // userDAO.setDataSource(dataSource);
    System.out.println("*****************/GRTBDashboard/retrieveTicketsToExcel****************");
    Map<String, String> requestMap = new Gson().fromJson(requestData, Map.class);

    response.reset();
    response.resetBuffer();

    response.setContentType("application/vnd.ms-excel");
    response.addHeader("Cache-control", "no-cache");
    response.setHeader("Content-disposition", "Attachment;filename=\"Ticket_Details.xls\"");
    ServletOutputStream fileOut = response.getOutputStream();

    System.out.println("retrieveTickets - > " + requestData);
    List<DashboardData> dashboardDataList = null;
    String tower = requestMap.get("tower");
    System.out.println(tower);
    try {
        dashboardDataList = userDAO.retrieveTickets(requestMap);
    } catch (SQLException e) {
        e.printStackTrace();
    } catch (ParseException e) {
        e.printStackTrace();
    }

    final double noOfRecords = dashboardDataList.size();
    double count = Math.ceil(noOfRecords / 30000);
    try {

        HSSFWorkbook workbook = new HSSFWorkbook();
        short dateFormat = workbook.createDataFormat().getFormat("YYYY-MM-DD HH:mm");

        Iterator<DashboardData> iterator = dashboardDataList.iterator();

        for (int i = 1; i <= count; i++) {
            int c1 = 1;
            HSSFSheet sheet = workbook.createSheet(tower);

            HSSFCellStyle style = workbook.createCellStyle();
            HSSFFont font = workbook.createFont();
            font.setFontName("Verdana");
            style.setFillForegroundColor(HSSFColor.GREY_40_PERCENT.index);
            style.setFillPattern(style.SOLID_FOREGROUND);
            font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
            font.setColor(HSSFColor.BLACK.index);
            style.setFont(font);
            HSSFRow header = sheet.createRow(0);
            ;

            header.createCell((short) 0).setCellValue(new HSSFRichTextString("Type"));
            header.getCell((short) 0).setCellStyle(style);

            header.createCell((short) 1).setCellValue(new HSSFRichTextString("Ticket Number"));
            header.getCell((short) 1).setCellStyle(style);

            header.createCell((short) 2).setCellValue(new HSSFRichTextString("Open Date"));
            header.getCell((short) 2).setCellStyle(style);

            header.createCell((short) 3).setCellValue(new HSSFRichTextString("Closed Date"));
            header.getCell((short) 3).setCellStyle(style);

            header.createCell((short) 4).setCellValue(new HSSFRichTextString("Reported By"));
            header.getCell((short) 4).setCellStyle(style);

            header.createCell((short) 5).setCellValue(new HSSFRichTextString("Severity"));
            header.getCell((short) 5).setCellStyle(style);

            header.createCell((short) 6).setCellValue(new HSSFRichTextString("Assigned App"));
            header.getCell((short) 6).setCellStyle(style);

            header.createCell((short) 7).setCellValue(new HSSFRichTextString("Status"));
            header.getCell((short) 7).setCellStyle(style);

            int rowIndex = 1;

            while (iterator.hasNext() && c1 <= 30000) {
                DashboardData dashboardData = iterator.next();
                System.out.println("Data : "+dashboardData.getTicketNumber());
                HSSFRow row = sheet.createRow(rowIndex++);

                HSSFCell cell0 = row.createCell((short) 0);
                cell0.setCellValue(new HSSFRichTextString(dashboardData.getType()));

                HSSFCell cell1 = row.createCell((short) 1);
                cell1.setCellValue(new HSSFRichTextString(dashboardData.getTicketNumber()));

                HSSFCell cell2 = row.createCell((short) 2);
                cell2.setCellValue(new HSSFRichTextString(dashboardData.getOpenDate().toString()));

                HSSFCell cell3 = row.createCell((short) 3);
                cell3.setCellValue(new HSSFRichTextString(dashboardData.getClosedate().toString()));

                HSSFCell cell4 = row.createCell((short) 4);
                cell4.setCellValue(new HSSFRichTextString(dashboardData.getReportedBy()));

                HSSFCell cell5 = row.createCell((short) 5);
                cell5.setCellValue(new HSSFRichTextString(dashboardData.getPriority()));

                HSSFCell cell6 = row.createCell((short) 6);
                cell6.setCellValue(new HSSFRichTextString(dashboardData.getAssignedGroup()));

                HSSFCell cell7 = row.createCell((short) 7);
                cell7.setCellValue(new HSSFRichTextString(dashboardData.getStatus()));
                c1++;

            }
            for (int autosize = 0; autosize <= 10; autosize++) {

                sheet.autoSizeColumn((short) autosize);
            }

        }

        workbook.write(fileOut);
    } catch (FileNotFoundException e2) {
        e2.printStackTrace();
    } finally {
        if (null != fileOut)
            fileOut.close();
    }
    fileOut.close();
    fileOut.flush();
}

I am trying to flush out data as excel which i am writing but on clicking export button does all but giving download on jsp page. If i am trying to write using FileOutputStream() it is writing perfectly on my disc. But i want to use response.getOutputStream() to download in jsp page.

Answer 1

Perhaps the problem is in the JQuery side?

Can you get the download working by opening retrieveTicketsToExcel.htm manually in the browser? If so, then try using window.location.href="retrieveTicketsToExcel.htm" instead of JQuery's ajax();

Edit: I am now quite sure the problem is in the Query side. First of all, ajax requests can not initiate file download dialogs. window.location.href or submitting a form are your options here.

Also, you are providing json as a dataType in your ajax call. This is wrong because dataType specifies the type of data that you're expecting back from the server, not the format of the request you're sending ( http://api.jquery.com/jquery.ajax/ )

Edit2:

Your use of data:'requestData='+JSON.stringify(jsonData) is also problematic. You can not simply appent JSON string to an url. You need to encode it first. Try using data:'requestData='+ encodeURI(JSON.stringify(jsonData))

Or better yet, use a POST request since this seems semantically more correct. That way you would not need the requestData= part, but would also have to change the servlet code a bit. You'd need to read the json from Servlet inputStream or reader directly.

Something like this: new Gson().fromJson(request.getReader(), Map.class); ;