Format a number in Java to be three characters wide

graemef · 06-29-2009, 04:41 AM

I am using Java (for my sins) and want to display a number to always use three characters, but no joy.

Some snippets of what I have tried...

Code:

String msg = MessageFormat.format("{0,number,##0}%", (double) _size
            * TO_PERCENTAGE / containerSize);

Code:

NumberFormat percent = NumberFormat.getPercentInstance();
String msg = percent.format((double)_size * TO_PERCENTAGE / containerSize);

Code:

DecimalFormat decimal = new DecimalFormat("##0");
String msg = decimal.format(_size * TO_PERCENTAGE / containerSize)
            + "%";

Each work the same, which is print the number but left aligned without the spaces that I yearn for.

Is there any way to entice this behaviour out of the Format family of classes or do I have to do the padding myself?

Sergei Steshenko · 06-29-2009, 08:48 AM

Java, actually, has 'printf' - isn't it sufficient ?

graemef · 06-29-2009, 10:55 AM

Thanks for the hint printf() doesn't really help because I want the result in a String, but with a bit more searching I found that the following works:

Code:

String msg = String.format("%3d", _size * TO_PERCENTAGE / containerSize) + "%";