java两个map,一个map的key是另外一个map的value 两个map合并并根据key去重

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("id", 1);
        map1.put("value", 2);
        list.add(map1);

        Map<String, Object> map6 = new HashMap<String, Object>();
        map6.put("id", 1);
        map6.put("value", 2);
        list.add(map6);

        Map<String, Object> map5 = new HashMap<String, Object>();
        map5.put("id", 1);
        map5.put("value", 4);
        list.add(map5);

        Map<String, Object> map2 = new HashMap<String, Object>();
        map2.put("id", 1);
        map2.put("value", 5);
        list.add(map2);

        Map<String, Object> map3 = new HashMap<String, Object>();
        map3.put("id", 2);
        map3.put("value", 5);
        list.add(map3);

        Map<String, Object> map4 = new HashMap<String, Object>();
        map4.put("id", 2);
        map4.put("value", 4);
        list.add(map4);

        Map<String, Object> map7 = new HashMap<String, Object>();
        map7.put("id", 2);
        map7.put("value", 4);
        list.add(map7);
        //id相等value追加（合并id相同数据）
        System.out.println("原始数据：" + list);

        Map<String, Object> res = new HashMap<String, Object>();
        for (Map<String, Object> map : list) {
            String id = map.get("id").toString();
            String value = map.get("value").toString();
            if (res.containsKey(id)) {
                String oldVal = res.get(id).toString();
                value = oldVal + "," + value;
            }
            res.put(id, value);
        }
        System.out.println("合并后的数据：" + res);


        //值去重处理
        Map<String, Object> res2 = new HashMap<String, Object>();
        for (String key : res.keySet()) {
            String valArr[] = res.get(key).toString().split(",");
            Set<String> set = new HashSet<String>(Arrays.asList(valArr));
            String[] newArr = set.toArray(new String[set.size()]);
            String tarVal = StringUtils.join(newArr,",");
            res2.put(key,tarVal);
        }
        System.out.println("去重后的数据：" + res2);
    }

输出：