枚举写法

/**
 *
 */
private static Map<String, CardKeyEnum> cardKeyEnumMap = Maps.newHashMap();

static {
    for (CardKeyEnum cardKeyEnum : CardKeyEnum.values()) {
        cardKeyEnumMap.put(cardKeyEnum.getKey(), cardKeyEnum);
    }
}

/**
 * @return
 */
public static CardKeyEnum getCardKeyEnumByKey(String key) {
    return cardKeyEnumMap.get(key);
}