JAVA计算生肖

public static String getZodiac(String key)
    {
        String str="鼠猪狗鸡猴羊马蛇龙兔虎牛";
        Integer year = Integer.valueOf(key.substring(0,4));
        Integer now = Integer.valueOf(getDate().substring(0,4));
        Integer num = (now-year-1)%12;
        return str.substring(num,num+1);
    }