Map的键key转换为全大写

public static void main(String[] args) {
        ArrayList<LinkedHashMap<String, Object>> mapArr = new ArrayList<>();
        LinkedHashMap<String, Object> linked = new LinkedHashMap<>();
        linked.put("key1","value1");
        linked.put("key2","value2");
        linked.put("key3","value3");
        LinkedHashMap<String, Object> linked1 = new LinkedHashMap<>();
        linked1.put("keY1","va1");
        linked1.put("kEy2",223);
        linked1.put("KEY3",false);
        mapArr.add(linked);
        mapArr.add(linked1);
        System.out.println();
        mapArr.forEach(System.out::println);
        // stream流转换
        List<LinkedHashMap<String, Object>> hashMaps = mapArr.stream()
                .map(map -> {
                    LinkedHashMap<String, Object> linkedMap = new LinkedHashMap<>();
                    map.forEach((key, value) -> linkedMap.put(key.toUpperCase(), value));
                    return linkedMap;
                })
                .collect(Collectors.toList());
        System.out.println(hashMaps);

        Map<String, Object> upperCase = transformUpperCase((Map<String, Object>) linked1);
        System.out.println(upperCase);
        Map<String, Object> lowerCase = transformLowerCase((Map<String, Object>) linked1);
        System.out.println(lowerCase);
    }
    // 将map的Key全部转换为大写
    public static Map<String,Object> transformUpperCase(Map<String,Object> orgMap){
        HashMap<String, Object> resultMap = new HashMap<>();
        if (orgMap == null || orgMap.isEmpty()){
            return resultMap;
        }
        Set<String> keySet = orgMap.keySet();
        for (String key : keySet){
            String newKey = key.toUpperCase();
            resultMap.put(newKey,orgMap.get(key));
        }
        return resultMap;
    }
    // 将map的Key全部转换为小写
    public static Map<String,Object> transformLowerCase(Map<String,Object> orgMap){
        HashMap<String, Object> resultMap = new HashMap<>();
        if (orgMap == null || orgMap.isEmpty()){
            return resultMap;
        }
        Set<String> keySet = orgMap.keySet();
        for (String key : keySet){
            String newKey = key.toLowerCase();
            resultMap.put(newKey,orgMap.get(key));
        }
        return resultMap;
    }