Tools-stream遍历

//使用stream来遍历

ArrayList<String> arrayList = new ArrayList<String>();
arrayList.add("111111");
arrayList.add("222222");
arrayList.add("333333");
Stream<String> stream = arrayList.stream();

stream.forEach(s-> System.out.println(s));

//或

stream.forEach(System.out::println);

// parallelStream来遍历集合  并行流会使用多线程

ArrayList<String> arrayList = new ArrayList<String>();
arrayList.add("111111");
arrayList.add("222222");
arrayList.add("333333");
Stream<String> stream = arrayList.parallelStream();

//stream.forEach(s-> System.out.println(s));
stream.forEach(System.out::println);

//arrays 创建流

String [] str ={ "11111","22222","33333"};
Stream<String> stream = Arrays.stream(str);
//stream.forEach(s-> System.out.println(s));
stream.forEach(System.out::println);

//of方法

String [] str ={ "11111","22222","33333"};
Stream<String> stream = Stream.of(str);
//stream.forEach(s-> System.out.println(s));
stream.forEach(System.out::println);

Stream<Integer> stream = Stream.of(1, 2, 3, 4, 5, 6, 7);
//stream.forEach(s-> System.out.println(s));
stream.forEach(System.out::println);

// iterate 创建流

//从0开始，每次增加2个  取前5个数据进行输出
Stream<Integer> stream = Stream.iterate(0, x -> 2);
stream.limit(5).forEach(System.out::println);

//取前5个随机数据进行输出
Stream<Integer> stream = Stream.generate(() -> new Random().nextInt(100));
stream.limit(5).forEach(System.out::println);

// IntStream  LongStream  DoubleStream  

IntStream intStream = IntStream.of(1, 2, 3, 4);
intStream.forEach(s -> System.out.println());

LongStream longStream = LongStream.of(1,2,3,4,5);
longStream.forEach(System.out::println);

DoubleStream doubleStream = DoubleStream.of(1, 2, 3, 4, 5);
doubleStream.forEach(a -> System.out.println(a));

//输出0-50   IntStream  LongStream  DoubleStream 的of range rangeClosed
IntStream range = IntStream.range(0, 50);
range.forEach(s-> System.out.println(s));

LongStream rangeLong = LongStream.range(0, 50);
rangeLong.forEach(s-> System.out.println(s));