jasperreport pdf auto download but empty

[cool3690]

I have a problem 

I want to download PDF automatically

I also have data input and show on web is ok

but when my pdf download ,it always blank

why?

<%       String Lang3="";      Object sql1=session.getAttribute("Lang2");              if(sql1!=null){Lang3=sql1.toString();}//sql data          ResultSet rs = stmt.executeQuery(Lang3);         File reportFile = new File(application.getRealPath("/report/report3.jasper"));              File reportFile2 = new File(application.getRealPath("/report/report3.jrxml"));            Map parameters = new HashMap();           JRDataSource dataSource = new JRResultSetDataSource(rs);             byte[] bytes = JasperRunManager.runReportToPdf(reportFile.getPath(), parameters, dataSource);             response.setContentType("application/pdf");            response.setContentLength(bytes.length);            ServletOutputStream outStream = response.getOutputStream();           JasperPrint print = JasperFillManager.fillReport(reportFile.toString(), parameters, dataSource);               JRPdfExporter exporter = new JRPdfExporter();            exporter.setParameter(JRExporterParameter.JASPER_PRINT, print);            exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, outStream);                       response.setHeader("Content-Disposition", "attachment;filename=" + "a" + ".pdf");            exporter.exportReport();            outStream.write(bytes, 0, bytes.length);            outStream.flush();            outStream.close();             rs.close();%>[/code]

thanks

[vchiem]

Maybe its font related where the font is not available to PDF export. Check these sections on how to embed fonts in PDF.  

Studio User guide: CHAPTER 9 FONTS

Server Admin guide: 5.7.1 Fonts

"when exporting the report to PDF, you may need to take additional steps if the report includes fonts"