list

翻转

    public static void main(String[] args) {
        List<Integer> integerList = Lists.newArrayList(1, 2, 3, 4, 5, 6);
        System.out.println(integerList);
        Collections.reverse(integerList);
        System.out.println(integerList);
    }

[1, 2, 3, 4, 5, 6]
[6, 5, 4, 3, 2, 1]

取子集

    public static void main(String[] args) {
        List<Integer> integerList = Lists.newArrayList(1, 2, 3, 4, 5, 6);
        System.out.println(integerList);
        System.out.println(integerList.subList(0, integerList.size() - 1));
        System.out.println(integerList.subList(1, integerList.size() - 1));
        System.out.println(integerList.subList(1, integerList.size()));
        System.out.println(integerList.subList(0, integerList.size()));
    }

[6, 5, 4, 3, 2]
[5, 4, 3, 2]
[5, 4, 3, 2, 1]
[6, 5, 4, 3, 2, 1]

map

    public static void main(String[] args) {
        Map<Integer, List<Integer>> resultMap = Maps.newHashMap();
        resultMap.put(1, Lists.newArrayList(2, 3, 4));
        resultMap.put(2, Lists.newArrayList(5, 6, 7));
        System.out.println(resultMap.get(1));
        System.out.println(resultMap.get(2));

        resultMap.values().forEach(value -> Collections.reverse(value));
        System.out.println(resultMap.get(1));
        System.out.println(resultMap.get(2));
    }

[2, 3, 4]
[5, 6, 7]
[4, 3, 2]
[7, 6, 5]