How can I determine if a String is non-null and not only whitespace in Groovy?

问题

Groovy adds the isAllWhitespace() method to Strings, which is great, but there doesn't seem to be a good way of determining if a String has something other than just white space in it.

The best I've been able to come up with is:

myString && !myString.allWhitespace

But that seems too verbose. This seems like such a common thing for validation that there must be a simpler way to determine this.

回答1:

Another option is

if (myString?.trim()) {
  ...
}

回答2:

You could add a method to String to make it more semantic:

String.metaClass.getNotBlank = { !delegate.allWhitespace }

which let's you do:

groovy:000> foo = ''
===> 
groovy:000> foo.notBlank
===> false
groovy:000> foo = 'foo'
===> foo
groovy:000> foo.notBlank
===> true

来源：https://stackoverflow.com/questions/9168518/how-can-i-determine-if-a-string-is-non-null-and-not-only-whitespace-in-groovy