Left zero padded format numbers

Question

I want to format 4-digit numbers with left padded zeros and 5-digit numbers with no leading zeros so when e.g:

• I insert 124 it is formatted to 0124.
• 30 is formatted to 0030.
• When number >9999 then it has no zero padding.

I tried String.format("%05d", Integer.parseInt(something));

but when I format 124, I get 00124

Answer 1

Try %04d instead:

• 0 indicates what you're using to pad;
• 4 is the width of the number (you had 5 before);
• d represents an integer (incl. byte, short, int, long, bigint).

String.format("%04d", Integer.parseInt(something));