如何使用正则表达式在String中的[和]内获得匹配

Question

I have a requirement to get the matching string within square brackets [].

For eg., in a String input like "[***]qwerty" , I should get the match as "***" string.

The regex I used in vain is "\\\\[(.+)\\\\]"

My Java code is as below:

Pattern pattern = Pattern.compile(regex_custom_delimiter_pattern); //see regex above
Matcher matcher = pattern.matcher("[***]qwerty");
String delimiter = null;
if (matcher.find()) {
  delimiter = matcher.group(0);
}

Any help is appreciated..wondering what I'm missing in the regex that I used :(

Answer 1

That should work correctly, but you can use a more efficient expression if the value between [ and ] doesn't contain [ or ] literally:

\\[([^\\]]+)]

Or if the value can contain [ or ] then:

\\[(.+?)\\]

Also your main problem is that you are getting group 0 matcher.group(0) which is the entire match, your value is stored in group 1 so you need matcher.group(1) .

Answer 2

您需要组1而不是组0.组0是整个匹配。

delimiter = matcher.group(0);