Stream类常用操作

public class StreamDemo01 {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("张无忌");
        list.add("周芷若");
        list.add("赵敏");
        list.add("张强");
        list.add("张三丰");
        //遍历集合:使用面向对象的方式
        //fori循环,迭代器,foreach循环
//        for (String name : list) {
//            System.out.println(name);
//        }
        //体验一下Stream的优雅代码
        list.stream().forEach(s-> System.out.println(s));
    }
}

//a.集合获取流
ArrayList<String> arr1 = new ArrayList<String>();
Stream<String> s1 = arr1.stream();

HashSet<Integer> arr2 = new HashSet<Integer>();
Stream<Integer> s2 = arr2.stream();

//Map集合无法直接获取流
// 但是可以先获取键的集合再获取键流
HashMap<String,Integer> map = new HashMap<String, Integer>();
Stream<String> keyStream = map.keySet().stream(); //获取键流
Stream<Map.Entry<String,Integer>> entryStream = map.entrySet().stream(); //获取Entry流
//b.数组获取流
Stream<Integer> s3 = Stream.of(10,20,30,40);

Stream<String> s1 = Stream.of("jack","rose","marry","rom","jerry","hanny");