regex - Java regular expression to match _all_ whitespace characters

Question

I'm looking for a regular expression in Java which matches all whitespace characters in a String. "s" matches only some, it does not match   and similar non-ascii whitespaces. I'm looking for a regular expression which matches all (common) white-space characters which can occur in a Java String.

[Edit]

To clarify: I do not mean the string sequence " " I mean the sincle unicode character U+00A0 that is often represented by " ", e.g. in HTML, and all other unicode characters with a similar white-space meainig, e.g. "NARROW NO-BREAK SPACE" (U+202F), Word joiner encoded in Unicode 3.2 and above as U+2060, "ZERO WIDTH NO-BREAK SPACE" (U+FEFF) and any other character that can be regareded as white-space.

[Answer]

For my pupose, ie catching all whitespace characters, unicode + traditional, the following expression does the job:

[p{Z}s]

The answer is in the comments below but since it is a bit hidden I repeat it here.

Answer 1

  is not a whitespace character, as far as regexpes are concerned. You need to either modify the regexp to include those strings in addition to s, like /(s| |%20)/, or previously parse the string contents to get the ASCII or Unicode representation of the data.

You are mixing abstraction levels here.

If, what after a careful reread of the question seems to be the case, you are after a way to match all whitespace characters referring to standard ASCII plus the whitespace codepoints, p{Z} or p{Zs} will do the work.

You should really clarify your question because it has misled a lot of people (even making the correct answer to have some downvotes).