List<Integer> cts = new ArrayList<>(ctSets);
Set<Integer> ctSet = new HashSet<>(cts);
List<Integer> ctss = new ArrayList<>(ctSet);Arrays.asList()
实现 三者之间的互转
List<Object> list = new Arraylist<>();
List<Object> subList = list.subList(0, 5);其中subList(0, 5)取得的是下标为0到4的元素,不包含下标为5的元素.
















