JasperPrint jasperPrint = (JasperPrint)JRLoader.loadObject(sourceFile);
File destFile = new File(sourceFile.getParent(), jasperPrint.getName() + ".metadata.csv");
JRCsvMetadataExporter exporter = new JRCsvMetadataExporter();
exporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);
exporter.setParameter(JRExporterParameter.OUTPUT_FILE_NAME, destFile.toString());
exporter.exportReport();
System.err.println("CSV creation time : " + (System.currentTimeMillis() - start));
}