Java8如何构建一个Stream示例详解

List<Integer> list = Lists.newArrayList(1, 2, 3);
Stream<Integer> stream = list.stream(); 

String[] arr = new String[]{"a", "b", "c"};
Stream<String> stream = Arrays.stream(arr); 

Map<String, Object> map = Maps.newHashMap();
Stream<Entry<String, Object>> stream = map.entrySet().stream(); 

Stream<Integer> integerStream = Stream.of(1, 2, 3); 

long uniqueWords = 0;
try (Stream<String> lines = Files.lines(Paths.get("data.txt"), Charset.defaultCharset())) {
 uniqueWords = lines.flatMap(l -> Arrays.stream(l.split(" ")))
  .distinct()
  .count();
} catch (IOException e) {
 //
} 

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

Stream.iterate(new int[]{0, 1}, t -> new int[]{t[1], t[0] + t[1]})
  .limit(20)
  .map(t -> t[0])
  .forEach(System.out::println); 

IntSupplier fib = new IntSupplier() {
 private int previous = 0;
 private int current = 1;

 @Override
 public int getAsInt() {
  int oldPrevious = this.previous;
  int nextValue = this.previous + this.current;
  this.previous = this.current;
  this.current = nextValue;
  return oldPrevious;
 }
};
IntStream.generate(fib).limit(10).forEach(System.out::println);