Java Map中数据按照key进行排序

Posted 2022-04-20 程序员超时空

方法一：

static String mapSortedByKey(Map<String, String> param) 
        StringBuilder stringBuilder = new StringBuilder();
        ArrayList<String> keyList = new ArrayList<>(param.keySet());
        Collections.sort(keyList);
        for (int i = 0; i < keyList.size(); i++) 
            String key = keyList.get(i);
            if (i == keyList.size() - 1) 
                stringBuilder.append(key).append("=").append(param.getOrDefault(key, ""));
             else 
                stringBuilder.append(key).append("=").append(param.getOrDefault(key, "")).append("&");
            
        
        return stringBuilder.toString();
    

测试：

Map<String, String> param = new HashMap<>();
        param.put("type", "1");
        param.put("user_mobile", "2");
        param.put("full_name", "3");
        param.put("id_no", "4");
        param.put("secret", "5");

        System.out.println(mapSortedByKey(param));

方法二：使用treeMap直接变为有序的map

    static void sortMap(Map<String, String> param) 
        TreeMap<String, String> paramTreeMap = new TreeMap<>(param);
        System.out.println(paramTreeMap);
    

    public static void main(String[] args) 
        HashMap<String, String> paramHashMap = new HashMap<String, String>() 
            
                put("type", "1");
                put("user_mobile", "2");
                put("full_name", "3");
                put("id_no", "4");
                put("secret", "5");
            
        ;
        sortMap(paramHashMap);