Using Java to find substring of a bigger string using Regular Expression

Question

If I have a string like this:

FOO[BAR] 

I need a generic way to get the "BAR" string out of the string so that no matter what string is between the square brackets it would be able to get the string.

e.g.

FOO[DOG] = DOG FOO[CAT] = CAT 

Answer 1

You should be able to use non-greedy quantifiers, specifically *?. You're going to probably want the following:

Pattern MY_PATTERN = Pattern.compile("\\[(.*?)\\]"); 

This will give you a pattern that will match your string and put the text within the square brackets in the first group. Have a look at the Pattern API Documentation for more information.

To extract the string, you could use something like the following:

Matcher m = MY_PATTERN.matcher("FOO[BAR]"); while (m.find()) {     String s = m.group(1);     // s now contains "BAR" }