java获取指定日期之前或之后的时间

/**
     * 前/后?分钟
     * 
     * @param d
     * @param minute
     * @return
     */
    public static Date rollMinute(Date d, int minute) {
        return new Date(d.getTime() + minute * 60 * 1000);
    }

    /**
     * 前/后?天
     * 
     * @param d
     * @param day
     * @return
     */
    public static Date rollDay(Date d, int day) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(d);
        cal.add(Calendar.DAY_OF_MONTH, day);
        return cal.getTime();
    }

    /**
     * 前/后?月
     * 
     * @param d
     * @param mon
     * @return
     */
    public static Date rollMon(Date d, int mon) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(d);
        cal.add(Calendar.MONTH, mon);
        return cal.getTime();
    }

    /**
     * 前/后?年
     * 
     * @param d
     * @param year
     * @return
     */
    public static Date rollYear(Date d, int year) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(d);
        cal.add(Calendar.YEAR, year);
        return cal.getTime();
    }

    public static Date rollDate(Date d, int year, int mon, int day) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(d);
        cal.add(Calendar.YEAR, year);
        cal.add(Calendar.MONTH, mon);
        cal.add(Calendar.DAY_OF_MONTH, day);
        return cal.getTime();
    }