Stupid java string padding question

MOH · 19-08-2009 03:32PM #1

Haven't used java much, and struggling with something very basic.
I need to pad some strings to a fixed length. As String.format() isn't recognised, I'm obviously on 1.4.2, which doesn't seem to have the Formatter object.

I'm presuming there's some handy way of doing this that I'm missing? (rather than just looping and concatenating spaces?)

Tried using a StringBuffer and setting its length, but that's not working out line I'd hoped.

Any suggestions?

onemorechance · 19-08-2009 03:48PM

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html

ronivek · 19-08-2009 03:58PM

Why do you want to pad it out? Are there particular values you want to use as your padding? What way are you creating or manipulating these Strings?

I don't think there are any shortcuts readily available to pad out a String barring using byte arrays of fixed length. Is there a pressing need for good performance or why are loops not suitable?

MOH · 19-08-2009 04:12PM

onemorechance wrote: »

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html

Thanks, but I've been through that. Unless I've missed it, there's nothing helpful there?

ronivek wrote: »

Why do you want to pad it out? Are there particular values you want to use as your padding? What way are you creating or manipulating these Strings?

I'm calling a web service, pulling certain node values out of the response, and writing those to a file to be read by a COBOL program, so they have to be formatted to the expected fixed length.

I don't think there are any shortcuts readily available to pad out a String barring using byte arrays of fixed length. Is there a pressing need for good performance or why are loops not suitable?

Nothing wrong with a loop, I just thought there'd be some kind of sprintf equivalent that I was missing, but that only seems to be in 1.5.

19-08-2009 04:29PM

Well (assuming I've understood this right, something which I can't guarantee), one simple way to do it is to just concatenate the String being returned with a String of spaces, then call substring. So, assuming you wanted every string to be of length 30:

String blank = "                              "; // 30 spaces
value = (value + blank).substring(0, 30);

Civilian_Target · 19-08-2009 08:00PM

I'm often in old 1.4 code, and I use Apache StringUtils, it fleshes out a lot of the missing stuff in 1.4

http://commons.apache.org/lang/api/index.html

boars.ie · 23-08-2009 01:29PM

28064212 wrote: »

String blank = "                              "; // 30 spaces
value = (value + blank).substring(0, 30);

Nice one, couldn't possibly be simpler,
maybe if explicit blank declaration was avoided

Stupid java string padding question

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