list<map<String,Object>>取某个属性的最值

List<Map<String,Object>> list = new ArrayList<>();
        Map<String, Object> map1 = new HashMap<>();
        map1.put("date","20220101");
        Map<String, Object> map2 = new HashMap<>();
        map2.put("date","20220102");
        Map<String, Object> map3 = new HashMap<>();
        map3.put("date","20200102");
        list.add(map1);
        list.add(map2);
        list.add(map3);
        int max = list.stream().mapToInt(e -> new Integer(String.valueOf(e.get("date")))).max().orElse(0);
        int min = list.stream().mapToInt(e -> new Integer(String.valueOf(e.get("date")))).min().orElse(0);
        System.out.println(max);
        System.out.println(min);