lambda表达式

public static void main(String[] args) {
 List<String> list = Arrays.asList("1","2","4","3","2","1","2");
 // 须要迭代list做处理
 list.forEach(s -> System.out.print(s));

 // 须要根据list中对象判断取出小集合
 List<String> list1 = list.stream().filter(s -> s.equals("1")).collect(Collectors.toList());
 System.out.print(list1);

 // 须要操做list对象组成新集合
 List list2 = list.stream().filter(s -> s.equals("1")).map(s -> s+1).collect(Collectors.toList());
 System.out.print(list2);}