map排序，根据key给map排序，根据value给map排序

    public static void main(String[] args) {
        Map<Integer,String> map = new TreeMap<>(new Comparator<Integer>(){
            @Override
            public int compare(Integero1, Integer o2) {
                return o1-o2;//按照key顺序排列，o2-o1是逆序
            }
        });
        map.put(3, "China");
        map.put(8, "America");
        map.put(2, "Canada");
        map.put(1, "Franch");
        map.put(5, "Banana");
//map遍历
        Set<Integer> set = map.keySet();
        Iterator<Integer> iterator = set.iterator();
        while(iterator.hasNext()){
            Integer key2 = iterator.next();
            System.out.println(key2+"-------"+map.get(key2));
        }
    }

    public static void main(String[] args) {
        TreeMap<Integer, String> map = new TreeMap<>();
        map.put(3, "China");
        map.put(8, "America");
        map.put(2, "Canada");
        map.put(1, "Franch");
        map.put(5, "Banana");

        ArrayList<Entry<Integer, String>> list =
                new ArrayList<Map.Entry<Integer, String>>(map.entrySet());

        Collections.sort(list, new Comparator<Map.Entry<Integer, String>>() {
            @Override
            public int compare(Entry<Integer, String> o1,
                               Entry<Integer, String> o2) {
                return o1.getValue().compareTo(o2.getValue());//顺序
            }
        });

        for (Entry<Integer, String> entry : list) {
            System.out.println(entry.getKey()+"------"+entry.getValue());
        }
    }