由值建立流

靜態方法Stream.of

Stream<String> stream = Stream.of("JAVA 8","Lambdas","In","Action");

由陣列建立流

靜態方法Arrays.stream

int[] numbers = {3,4,5,6,11,13};
int sum = Arrays.stream(numbers).sum();

由檔案生成流

java.nio.file.Files中很多靜態方法會返回一個流。例如Files.lines，返回檔案各行構成的字串流。

Stream<String> lines = Files.lines
 
(Paths.get("data.txt"),Charset.defaultCharset())

由函式生成流

• 迭代
  Stream.iterate

Stream.iterate(0,n->n+2)
      .limit(10)
      .forEach(System.out::println);

• 生成
  Stream.genarate

Stream.generate(Math::random)
      .limit(10)
      .forEach(System.out::println);