| This works with Hibernate 3 but should be ok for you: 
 ByteArrayOutputStream xlsReport = new ByteArrayOutputStream();
 InputStream inputStream;
 inputStream = new FileInputStream(reportFile.getPath());
 
 JRXlsExporter xlsExporter = new JRXlsExporter();
 
 JasperPrint jasperPrint =
 JasperFillManager.fillReport(
 inputStream,
 params,
 new JRBeanCollectionDataSource(StoreVoucherList)
 );
 
 xlsExporter.setParameter(JRXlsExporterParameter.JASPER_PRINT, jasperPrint);
 xlsExporter.setParameter(JRXlsExporterParameter.OUTPUT_STREAM, xlsReport);
 xlsExporter.setParameter(JRXlsExporterParameter.IS_ONE_PAGE_PER_SHEET, Boolean.FALSE);
 xlsExporter.setParameter(JRXlsExporterParameter.IS_WHITE_PAGE_BACKGROUND, Boolean.TRUE);
 xlsExporter.setParameter(JRXlsExporterParameter.IS_REMOVE_EMPTY_SPACE_BETWEEN_ROWS, Boolean.TRUE);
 xlsExporter.exportReport();
 
 OutputStream ouputStream = response.getOutputStream();
 ouputStream.write(xlsReport.toByteArray());
 ouputStream.flush();
 ouputStream.close();
 
 
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