// Create a new workbook Workbook workbook = new Workbook(); IWorksheet worksheet = workbook.getWorksheets().get(0); //1:20 rows' outline level will be 2. worksheet.getRange("1:20").group(); //1:10 rows' outline level will be 3. worksheet.getRange("1:10").group(); //1:20 rows' outline level will be 1. worksheet.getRange("11:11").setShowDetail(false); // Save to an excel file workbook.save("CollapseGroup.xlsx");