Java regex - expression with exactly one whitespace

Question

I want to match all expressions with exactly one whitespace. Currently, I\'m using [^\\\\s]*\\\\s[^\\\\s]*. That doesn\'t seem like a very good way, though.

Answer 1

String[] ss = { " ", "abc", "a bc", "a b c d" };
Matcher m = Pattern.compile("^\\S*\\s\\S*$").matcher("");
for (String s : ss)
{
  if (m.reset(s).matches())
  {
    System.out.printf("%n>>%s<< OK%n", s);
  }
}

output:

>> << OK

>>a bc<< OK