Birt报告未以PDF格式打开

Hello guys I am sending my form values to controller and controller to rptdesign file my it is generating the report in temp folder with proper value but my requirement is that it should user to save or open dialog so that user can save the report or open i think ajax request will not allow to download any file so if some one know to better solution plz reply

my controller is below

@RequestMapping("/leave/generateEmpLeaveReport.json")
public void generateEmployeeLeaveReport(HttpServletRequest request,
        HttpServletResponse response) throws Exception {
    String reportName = "D:/git-repositories/cougar_leave/src/java/com//report/myLeaveSummary.rptdesign";
    File designTemplateFile = new File(reportName);
    if (!designTemplateFile.exists()) {
        throw new FileNotFoundException(reportName);
    }

    Map<String, Object> parameters = new HashMap<String, Object>();
    parameters.put("empId", NumberUtils.toInt(request.getParameter("id")));
    parameters.put("reportTitle", "EMPLOYEE LEAVE");
    parameters.put("fromDate", request.getParameter("fromDate"));
    parameters.put("toDate", request.getParameter("toDate"));
    parameters.put("leaveType",
            NumberUtils.toInt(request.getParameter("leaveType")));
    parameters.put("transactionType",
            NumberUtils.toInt(request.getParameter("transactionType")));
    reportManager.addSystemParams(parameters, null,
            RequestUtils.getUser(request));
    File file = null;
    try {
        ReportType reportType = ReportType.PDF;
        OfflineReportContext reportContext = new OfflineReportContext(
                reportName, reportType, parameters, null,
                "EMPLOYEE LEAVE SUMMARY");

        StringBuffer buffer = new StringBuffer();
        file = offlineReportGenerator.generateReportFile(reportContext,
                buffer);
        ControllerUtils
                .openFile(file.getParent(), response, file.getName());
    } catch (Exception e) {
        log.error(e, e);
    } finally {
        if (file != null && file.exists()) {
            file.canExecute(); 
        }
    }

}

my ajax request is below

generateReport : function() {
        if (this.form.valid()) {
            fromDate = new Date($("input[name='fromDate']").val())
            toDate = new Date($("input[name='toDate']").val())
            if (fromDate > toDate) {
                GtsJQuery
                        .showError("To date should be greater or equals than From date !")
            } else {

                var request = GtsJQuery.ajax3(GtsJQuery.getContextPath()
                                + '/leave/generateEmpLeaveReport.json', {
                            data : {
                                id : $("input[name='employeeId']").val(),
                                fromDate : $("input[name='fromDate']")
                                        .val(),
                                toDate : $("input[name='toDate']").val(),
                                leaveType : $("select[name='leaveType']")
                                        .val(),
                                transactionType : $("select[name='transactionType']")
                                        .val(),
                                orderBy : $("select[name='orderBy']").val()
                            }
                        });
                request.success(this.callback("onSubscribeSuccess"))
            }
        }
    },

The controller response should be the temp file itself, just adjust the content-type.