我觉得这样的写法更简单： public static void getRandomNum() { Scanner in = new Scanner(System.in); while (in.hasNext()) { int input = in.nextInt(); List list = new ArrayList(); for (int i = 0; i < input; i++) { list.add(in.nextInt()); } List collect = (List) list.stream().distinct().sorted().collect(Collectors.toList()); for (int j = 0; j < collect.size(); j++) { System.out.println(collect.get(j)); } } }