Use Regular Expression to extract numbers in brackets

Question

Currently, I am struggling with the problem of catching numbers with REGEX by using Java

The string which I am trying to catch the numbers in this string value using REGEX is this..

[TEST][64894]HelloWorld[KGMObilians]

My wish is to catch the numbers which are located in [ ].

Would this be possible with Java? I could easily take the number by splitting the string, but the company wants me to use the regex since it is more safer and faster. please help me.

Answer 1

Try this:

String s = "[TEST][64894]HelloWorld[KGMObilians]";
Pattern patt = Pattern.compile("\\[\\d+\\]");
Matcher match = patt.matcher(s);

IDEONE DEMO

And if you dont want the brackets then simply make it like

String s = "[TEST][64894]HelloWorld[KGMObilians]";
Pattern patt = Pattern.compile("\\[(\\d+)\\]");
Matcher match = patt.matcher(s);
while(match.find()){
    System.out.println(match.group(1));
}

IDEONE DEMO