I can not export or convert Jasper report in PDF

Good morning friends, I can not export a jasperreport in PDF, what I want is to save it in the url that sent it, I use ireport 4.0.1 I am working with java 1.8 IDE netbeans 8.2, or they will have another example friends

     String dirDownload = "C:\Reportes\";
     String ext=".pdf";
     String nameFile= String.valueOf(boletito.getIdboleto()) ;
     report=(JasperReport) 

     JRLoader.loadObject(getClass()
     .getResource("/reportes/boletoviajeCPE.jasper"));

            Map parameters = new HashMap();
            parameters.put("v_idboleto",boletito.getIdboleto());
            parameters.put("v_valorenletra","");

           JasperPrint print = JasperFillManager.fillReport(report, 
           parameters,conn);
           JRExporter exporter = new JRPdfExporter();
           exporter.setParameter(JRExporterParameter.JASPER_PRINT, print);
           System.out.println(dirDownload + nameFile + ext);

           exporter.setParameter(JRExporterParameter.OUTPUT_FILE, new 
           java.io.File(dirDownload, nameFile + ext)); 

           exporter.exportReport();