Table of contents

Formatter

create a formatter

Formatter formatter = new Formatter(sb, Locale.US);
String s = formatter.format(format, arg...);

convenience method

String.format(format, arg...);

formatting syntax

general

format syntax

%[flags][width][.precision]conversion-character

newline

String.format("%n")

numbers

integer

format an integer

String.format("%d", [number]);           plain number
String.format("%,d", [number]);          separate thousands with ','
String.format("%9d", [number]);          leftpad with spaces
String.format("%09d", [number]);         leftpad with zeroes
String.format("%-9d", [number]);         rightpad with spaces

float

format a float

String.format("%f", [float]);            plain number
String.format("%,f", [float]);           separate thousands with ','
String.format("%.2f", [float]);          2 decimal digits

date / time

time

String.format("%tT", new Date());      human readable time

documentation

https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/Formatter.html#syntax