To export into Excel format I use this code. Check if it works for you. Cheers! Code:JasperPrint print = JasperFillManager.fillReport(fileName, parameters, dataSource); JRExporter exporter = new JRXlsExporter(); exporter.setParameter(JRExporterParameter.OUTPUT_FILE_NAME, outFileName); exporter.setParameter(JRExporterParameter.JASPER_PRINT, print); exporter.exportReport(); File archivo = new File(outFileName); FileInputStream fis = new FileInputStream(outFileName); ByteArrayOutputStream bos = new ByteArrayOutputStream(); byte[] buf = new byte[1024]; try { for (int readNum; (readNum = fis.read(buf)) != -1;) { bos.write(buf, 0, readNum); } } catch (IOException ex) { ex.printStackTrace(); } bytes = bos.toByteArray();