lambda表达式

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

    // 需要根据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);

    // 需要操作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);
}