如何在使用DecimalFormat时始终显示小数部分？

Question

Float sum = new Float(300); // always somehow calculated
DecimalFormat df = new DecimalFormat("#.#");
String s = df.format(sum/3);  // prints 100, I want 100.0
s = df.format(301/3); // pritns 100.3 which is correct

Result should always be formatted to 1 decimal palce, how to do so?

Answer 1

Change

DecimalFormat df = new DecimalFormat("#.#");

to

DecimalFormat df = new DecimalFormat("#.0");

Basically, a 0 means "always show the digit in this position", where a # means "show the digit in this position unless it's zero".

Answer 2

You can read about the patterns here . Change the following line to should do the trick.

DecimalFormat df = new DecimalFormat("#.0");