Java Stream - 如何输出值(如果存在)

import java.util.Optional;

public class Main {
   public static void main(String[] args) {
     Optional<String> optional1 = Optional.empty();
     Optional<String> optional2 = Optional.of("DEMO");

     System.out.println("optional2.get = " + optional2.get());
     System.out.println("optional1.orElse = " + optional1.orElse("Something else"));
     optional2.ifPresent(System.out::println);
     System.out.println("optional1.isPresent = " + optional1.isPresent());

   }

}