Java基础之集合List<map>进行排序

现有以下集合List<Map<String,String>>，

集合中元素Map中主要包含“code”，“name”等属性，

要求按code升序，name降序的顺序对集合进行重新排序；

实现Collections接口进行排序

1，先根据需求封装List<Map<String,String>>

 public static void main(String[] args) {
        List<Map<String, String>> list = new ArrayList<>();
        Map<String, String> mapOne = new HashMap<>();
        mapOne.put("code", "001");
        mapOne.put("name", "小a");

        Map<String, String> mapTwo = new HashMap<>();
        mapTwo.put("code", "003");
        mapTwo.put("name", "小b");

        Map<String, String> mapThree = new HashMap<>();
        mapThree.put("code", "002");
        mapThree.put("name", "小c");
        list.add(mapOne);
        list.add(mapTwo);
        list.add(mapThree);

        //进行排序
        List<Map<String, String>> listResult = listSort(list);
        //控制台打印
        for (Map<String, String> map : listResult) {
            System.out.println("编号：" + map.get("code") + ",姓名：" + map.get("name"));
        }
    }

2，根据问题，调用Conllections方法进行两次排序

    public static List<Map<String, String>> listSort(List<Map<String, String>> list) {

        //实现Collections接口进行排序
        Collections.sort(list, new Comparator<Map<String, String>>() {
            @Override
            public int compare(Map<String, String> o1, Map<String, String> o2) {
                return o1.get("code").compareTo(o2.get("code"));
            }
        });

        //在对已经排序完成的进行降序
        Collections.sort(list, new Comparator<Map<String, String>>() {
            @Override
            public int compare(Map<String, String> o1, Map<String, String> o2) {
                return -o1.get("name").compareTo(o2.get("name"));
            }
        });


        return list;

    }

关于compareTo用法：

https://blog.youkuaiyun.com/Soinice/article/details/80662732