SpreadsheetMLPackage pkg = SpreadsheetMLPackage.createPackage();
WorksheetPart sheet = pkg.createWorksheetPart(new PartName("/xl/worksheets/sheet1.xml"), "Sheet1", 1);
addContent(sheet);
pkg.save(new File(outputfilepath));
System.out.println("\n\n done .. " + outputfilepath);
} catch (Exception e) {
e.printStackTrace();