No, there is no better way.
Actually you have an error in your pattern. What you want is:
DecimalFormat df = new DecimalFormat("#.00");
Note the "00", meaning exactly two decimal places.
If you use "#.##" (# means "optional" digit), it will drop trailing zeroes - ie new DecimalFormat("#.##").format(3.0d); prints just "3", not "3.00".