技术杂记 【JSONArray 按指定字段排序，升序和倒序】

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第一种

        Random random = new Random();
        JSONArray result = new JSONArray();
        for(int i = 0 ; i < 10 ; i++){
            JSONObject obj = new JSONObject();
            obj.put("value",random.nextInt(10));
            result.add(obj);
        }

        System.out.println("排序前: " + result.toJSONString());

        result.sort(Comparator.comparing(obj -> {
            Integer value = ((JSONObject) obj).getIntValue("value");
            return value;
        }));

        System.out.println("排序后(升序) :  " + result.toJSONString());

        result.sort(Comparator.comparing(obj -> {
            Integer value = ((JSONObject) obj).getIntValue("value");
            return value;
        }).reversed());
        System.out.println("排序后(降序) :  " + result.toJSONString());

输出结果：

排序前: [{"value":1},{"value":3},{"value":9},{"value":9},{"value":9},{"value":6},{"value":0},{"value":5},{"value":7},{"value":2}]
排序后(升序) :  [{"value":0},{"value":1},{"value":2},{"value":3},{"value":5},{"value":6},{"value":7},{"value":9},{"value":9},{"value":9}]
排序后(降序) :  [{"value":9},{"value":9},{"value":9},{"value":7},{"value":6},{"value":5},{"value":3},{"value":2},{"value":1},{"value":0}]

第二种

也可以自定义比较器

public class ValueComparator implements Comparator<JSONObject> {

    @Override
    public int compare(JSONObject o1, JSONObject o2) {
        Integer value1 = o1.getIntValue("value");
        Integer value2 = o2.getIntValue("value");
        return value1 - value2;
    }

        Random random = new Random();
        JSONArray result = new JSONArray();
        for(int i = 0 ; i < 10 ; i++){
            JSONObject obj = new JSONObject();
            obj.put("value",random.nextInt(10));
            result.add(obj);
        }

        System.out.println("排序前: " + result.toJSONString());

//        result.sort(Comparator.comparing(obj -> {
//            Integer value = ((JSONObject) obj).getIntValue("value");
//            return value;
//        }));

        List<JSONObject> list = new ArrayList<JSONObject>();
        for(int i = 0 ; i < result.size() ; i++){
            list.add((JSONObject) result.get(i));
        }

        Collections.sort(list,new ValueComparator());
        //重新装回JSONArray
        result.clear();
        for (JSONObject jsonObject : list) {
            result.add(jsonObject);
        }

        System.out.println("排序后(升序) :  " + result.toJSONString());

//        result.sort(Comparator.comparing(obj -> {
////            Integer value = ((JSONObject) obj).getIntValue("value");
////            return value;
////        }).reversed());

        System.out.println("排序后(降序) :  " +  result.toJSONString());

输出结果

排序前: [{"value":1},{"value":1},{"value":9},{"value":0},{"value":6},{"value":5},{"value":1},{"value":7},{"value":3},{"value":2}]
排序后(升序) :  [{"value":0},{"value":1},{"value":1},{"value":1},{"value":2},{"value":3},{"value":5},{"value":6},{"value":7},{"value":9}]
排序后(降序) :  [{"value":0},{"value":1},{"value":1},{"value":1},{"value":2},{"value":3},{"value":5},{"value":6},{"value":7},{"value":9}]

第二种只会根据你定义的比较器的规则来，如果又需要降序则需要另外定义规则，如果只是简单的排序规则，我推荐第一种