List> 对Map中k

public class Sort {
    public static void main(String[] args) {
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
        Map<String, Object> map1 = new HashMap<String, Object>();
        map1.put("name", "p");
        map1.put("cj", "5");
        Map<String, Object> map2 = new HashMap<String, Object>();
        map2.put("name", "h");
        map2.put("cj", "12");
        Map<String, Object> map3 = new HashMap<String, Object>();
        map3.put("name", "f");
        map3.put("cj", "31");
        Map<String, Object> map4 = new HashMap<String, Object>();
        map4.put("name", "f");
        map4.put("cj", "30");
        list.add(map1);
        list.add(map3);
        list.add(map2);
        list.add(map4);
        //排序前
        for (Map<String, Object> map : list) {
            System.out.println(map.get("cj"));
        }
        Collections.sort(list, new Comparator<Map<String, Object>>() {
            public int compare(Map<String, Object> o1, Map<String, Object> o2) {
                Integer name1 = Integer.valueOf(o1.get("cj").toString()) ;//name1是从你list里面拿出来的一个
                Integer name2 = Integer.valueOf(o2.get("cj").toString()) ; //name1是从你list里面拿出来的第二个name
                return name1.compareTo(name2);
            }
        });
        //排序后
        System.out.println("-------------------");
        int i = 1;
        for (Map<String, Object> map : list) {
            map.put("paiming",i);
            i++;
            System.out.println(map.toString());
        }
    }
}