获取指定分钟单位间隔前后的系统时间

/**
     * 取得指定分钟单位间隔后的系统时间
     */

    public static String getDifferentTimeByMinutes(int minutes) {
        GregorianCalendar calendar = (GregorianCalendar) Calendar.getInstance();
        calendar.add(Calendar.MINUTE, minutes);
        SimpleDateFormat formatter = new SimpleDateFormat(DEFAULT_TIME_FORMAT_DB);
        return formatter.format(calendar.getTime());
    }
    /**
     * 取得指定分钟单位间隔前的系统时间
     */

    public static String getDifferentTimeByBefore(int minutes) {
        GregorianCalendar calendar = (GregorianCalendar) Calendar.getInstance();
        calendar.set(Calendar.MINUTE,  calendar.get(Calendar.MINUTE) - minutes);
        SimpleDateFormat formatter = new SimpleDateFormat(DEFAULT_TIME_FORMAT_DB);
        return formatter.format(calendar.getTime());
    }