private static String transFromCamel(String key) {
        Matcher matcher = PATTERN.matcher(key);
        StringBuffer sb = new StringBuffer();
        while (matcher.find()) {
            matcher.appendReplacement(sb, "." + matcher.group(0).toLowerCase(Locale.ROOT));
        }
        matcher.appendTail(sb);
        return sb.toString();
    }
@Test
    public void testReadEnv() throws Exception {
        testKey(CONFIG_KEY);
        testKey(CONFIG_KEY.replace('.', '_'));
        testKey(CONFIG_KEY.replace('.', '-'));
        testKey(CONFIG_KEY.toLowerCase(Locale.ROOT).replace('.', '-'));
        testKey(CONFIG_KEY.toLowerCase(Locale.ROOT).replace('.', '_'));
        testKey(CONFIG_KEY.toLowerCase(Locale.ROOT));
        testKey(CONFIG_KEY.toUpperCase(Locale.ROOT).replace('.', '-'));
        testKey(CONFIG_KEY.toUpperCase(Locale.ROOT).replace('.', '_'));
        testKey(CONFIG_KEY.toUpperCase(Locale.ROOT));
        testKey(transFromCamel(CONFIG_KEY));
        testKey(transFromCamel(CONFIG_KEY).replace('.', '_'));
        testKey(transFromCamel(CONFIG_KEY).replace('.', '-'));
        testKey(transFromCamel(CONFIG_KEY).toUpperCase(Locale.ROOT));
        testKey(transFromCamel(CONFIG_KEY).toUpperCase(Locale.ROOT).replace('.', '_'));
        testKey(transFromCamel(CONFIG_KEY).toUpperCase(Locale.ROOT).replace('.', '-'));
    }