How to get first String based on whitespace out of a full String using java8?

Question

Let's Example I have String s = "Rahul Kumar" I need to have Rahul as a output using java8

Actual Requirement, I do have a list of Trip Object, I want to set driverName property as only first name to each Trip Object and return that list?

System.out.println( someStringValue.subSequence(0, someStringValue.indexOf(' ')));

I'm getting trouble to incorporate this code into the listOfTrip. If I'm doing like this,

List<CharSequence> list = listOfTrips.stream().map(e -> e.getDriverName().subSequence(0, someStringValue.indexOf(' '))).collect(Collectors.toList()); System.out.println(list); 

Here, With this, The return type is wrong and it is not fetching only first name out of full name.

Answer 1

Below will give you the proper result:

List<CharSequence> list2 = listOfTrips.stream()
                        .map(m->m.getDriverName().substring(0,m.getDriverName().indexOf(' ')))
                        .collect(Collectors.toList());

Answer 2

Please try this also once:

String s = "Rahul Kumar";
Optional<String> beforeWhiteSpace = Pattern.compile(" ").splitAsStream(s).collect(Collectors.toList()).stream().findFirst();