Concatenate string values with delimiter handling null and empty strings?

Question

In Java 8 I have some number of String values and I want to end up with a comma delimited list of valid values. If a String is null or empty I want to ignore it. I know this seems common and is a lot like this old question; however, that discussion does not address nulls AND spaces (I also don't like the accepted answer).

I've looked at Java 8 StringJoiner, Commons StringUtils (join) and trusty Guava (Joiner) but none seems like a full solution. The vision:

 where: val1 = "a", val2 = null, val3 = "", val4 = "b"

  String niceString = StringJoiner.use(",").ignoreBlanks().ignoreNulls()
    .add(val1).add(val2).add(val3).add(val4).toString();

...would result in niceString = a,b

Isn't there a nice way to do this (that doesn't involve for loops, loading strings into a list, and/or regex replaces to remove bad entries)?

Answer 1

String joined = 
    Stream.of(val1, val2, val3, val4)
          .filter(s -> s != null && !s.isEmpty())
          .collect(Collectors.joining(","));