Jxl. Writablecellformat Definition

You can set the border and background via the WritableCellFormat.setBorder() and WritableCellFormat.setBackground() methods after having instanciated your cell.

You can see the API there.

If you have to do that a lot, you can make a helper function like this :

public static makeCell(NumberFormat format, WritableFont font, Color backgrd, Border border){
    final WritableCellFormat result = new WritableCellFormat(defaultfont, numberformatter);
    result.setBorder(border);
    result.setBackground(backgrd);
    return result;
}

You Can do this by 2 steps

1. Create a WritableFont

2. Create a WritableCellFormat with WritableFont,NumberFormats as a parameter

Attaching the code snippet

int fontSize = 8;  
WritableFont wfontStatus = new WritableFont(WritableFont.ARIAL, fontSize);
wfontStatus.setColour(Colour.BLACK);
wfontStatus.setBoldStyle(WritableFont.BOLD);

WritableCellFormat fCellstatus = new WritableCellFormat(wfontStatus, NumberFormats.TEXT); // You can use any NumberFormats I have used TEXT for my requirement
try {
    fCellstatus.setWrap(true);
    fCellstatus.setBorder(Border.ALL,BorderLineStyle.THIN);
    fCellstatus.setAlignment(Alignment.CENTRE);
    fCellstatus.setBackground(Colour.YELLOW);
} 
catch (WriteException e) {
    e.printStackTrace();
 }