Question

considering we have following strings and we are going to write them into a text file:

String a="        "
String b="  "
String c="java "
String d=" java"
String e="java"

but because a and b has no character , we have no interest to insert them into the file.
maybe here its easy to see them and ignore them, but what if there is a DOM tree and we get nodes text one by one and because of lots of white spaces in the page, there are lots of white space strings like [#text: ] in the DOM .
what is the way to find out strings like a and b as blanks and then ignoring them to right it into a text?

Answer 1

s.trim().length() == 0;

or

s.trim().isEmpty();

or

s.matches("\\s*");

or

StringUtils.isBlank(s);

(that one needs Jakarta Commons Lang). I personally go with the last one as it’s null-safe to boot.