Please check the detailed article on how to set the background color of the cell. Following code sets the cell A1 background color to yellow of worksheet sheet2.
Java
//Instantiating a Workbook object
Workbook workbook = new Workbook(); //Accessing the added worksheet in the Excel file int sheetIndex = workbook.getWorksheets().add();
Worksheet worksheet = workbook.getWorksheets().get(sheetIndex);
Cells cells = worksheet.getCells(); //Accessing the “A1” cell from the worksheet
Cell cell = cells.get(“A1”);
Style style = cell.getStyle(); //Setting the cell color to yellow
style.setForegroundColor(Color.getYellow()); //Setting the background pattern to vertical stripe
style.setPattern(BackgroundType.SOLID); //Saving the modified style to the “A1” cell.
cell.setStyle(style); //Saving the Excel file
workbook.save(“D:/output.xls”);