java format strings based on a pattern

Question

I have a requirement like this. My code generates random strings and it can be alpha, numeric and alphanumeric ones.

Lets say one of the numeric strings are "7882347812". I want to format this to 788.234.7812 based on a pattern like 3chars.3chars.4chars

If its an alphanumeric one like "h34jh8we7k". Then format this to h3/4jh8/we7k based on a pattern like 2chars/4chars/4chars.

If its an alpha one like "jkythjyv". Then format this to jky$thj$yv based on a pattern like 3chars$3chars$2chars.

In general, the generated strings can contain chars [a-zA-Z0-9]. This should be formatted as I mentioned above with any of the special characters. The input should be the string & the formatter and output should be the formatted string. Even a custom formatter is also fine.

I know how to write code for this. Is there any standard way of doing this in Java?

I assume you're trying to format phone numbers. There are several answers to this question already. Here, here, and here — Cory Klein
– Cory Klein, Commented Oct 1, 2014 at 16:54

Ani · Accepted Answer · 2014-10-01 20:25:14Z

8

I got a solution for this:

MaskFormatter formatter = new MaskFormatter("A-AAAA-AAAA-A");
formatter.setValueContainsLiteralCharacters(false);
System.out.println(formatter.valueToString("1222233334"));

The output would be 1-2222-3333-4

Check http://docs.oracle.com/javase/7/docs/api/javax/swing/text/MaskFormatter.html for more details

answered Oct 1, 2014 at 20:25

Ani

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2 Comments

Cory Klein Over a year ago

That is yet another creative solution! Good job.

artem Over a year ago

Not applicable for Android

Avinash Raj · Accepted Answer · 2014-10-01 17:38:24Z

7

You could do this through replaceAll function.

System.out.println("7882347812".replaceAll("^(\\d{3})(\\d{3})(\\d{4})$", "$1.$2.$3"));

Output:

788.234.7812

OR

System.out.println("foo bar 7882347812".replaceAll("\\b(\\d{3})(\\d{3})(\\d{4})\\b", "$1.$2.$3"));

Output:

foo bar 788.234.7812

edited Oct 1, 2014 at 17:38

answered Oct 1, 2014 at 16:50

Avinash Raj

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2 Comments

Ryan J Over a year ago

This implies the whole string is a 10-digit string, while in his post he said "My code generates random strings and it can be alpha, numeric and alphanumeric ones", which means it could result in strings +/-10 characters, with more than just numbers. Your example could probably update to account for that and answer the question more completely (though I do note the ambiguity of the request, so there's that...)

Avinash Raj Over a year ago

then it would be \\b(\\d{3})(\\d{3})(\\d{4})\\b

vks · Accepted Answer · 2014-10-01 16:54:10Z

0

^(.{3})(.{3})(.{4})$

Try this.This will work.See demo.

http://regex101.com/r/xP1dE9/1

answered Oct 1, 2014 at 16:54

vks

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4 Comments

Cory Klein Over a year ago

Whoa! regex101 is neat! As a side note, that might not work for the OP because it also accepts alpha characters.

vks Over a year ago

@CoryKlein OP says random string generated can be alpha numeric etc.

Cory Klein Over a year ago

Yea, it's ambiguous. His example gave a strictly numeric string, so I was assuming he only wanted to apply the pattern to numeric strings. (shrug) Whatever.

Cory Klein Over a year ago

@Ani My answer still holds. No, there is not a standard way of doing this in Java. There are ways that work and ways that don't. There are elegant ways, and ugly ways.

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