Java regex stop after first occurrence

Question

When using code like the following:
while (matcher.find()) {
string1=matcher.group(1).trim();
System.out.println(charset);
the program goes on looking all through the input string and prints out the final match.
What should be done to find the first occurrence and to stop searching through the input string after the first match has been found? i.e. I want to exit the while loop after the first match is found.

Answer 1

The first .* in your regex matches as much as it can at first, and becuase you used the DOTALL flag, it's able to gobble up the whole remaining string. Then it starts backtracking, trying to match the rest of the regex, and it has to backtrack almost all the way to beginning of the string again before it gets back to the META tag where it's supposed to match (unless it finds a false match elsewhere first). That's just an example of greedy quantifiers at work; by calling it a loop you sent us all barking up the wrong scent trail.
Making that dot-star reluctant is not the solution though; the regex would then match everything from the first occurrence of "<meta" to the first occurrence of "charset", where "charset" could be in a separate META tag or just hanging loose later in the string. Getting rid of the DOTALL flag might restrict the match to just one META tag, but you can't count on that. Try this: REGEX = "<meta\\s[^<>]*?charset=([^\\s\"]+)";
pattern = Pattern.compile(REGEX, Pattern.CASE_INSENSITIVE); // the only flag you need{code} Also, if you aren't familiar with this website, you'll probably find it useful:
http://www.regular-expressions.info/