/**	 * 从当前日期算起，获取N天前的日期（当前日不算在内），日期格式为yyyy-MM-dd	 * 	 * @param daily 天数	 * @return 	 */	public static String getDateByDay(Integer daily) {		Date date = new Date();		int year = Integer.parseInt(new SimpleDateFormat("yyyy").format(date));		int month = Integer.parseInt(new SimpleDateFormat("MM").format(date));		int day = Integer.parseInt(new SimpleDateFormat("dd").format(date)) - daily;		if (day < 1) {			month -= 1;			if (month == 0) {				year -= 1;				month = 12;			}			if (month == 4 || month == 6 || month == 9 || month == 11) {				day = 30 + day;			} else if (month == 1 || month == 3 || month == 5 || month == 7					|| month == 8 || month == 10 || month == 12) {				day = 31 + day;			} else if (month == 2) {				if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {					day = 29 + day;				}				else {					day = 28 + day;				}			}		}		String y = year + "";		String m = "";		String d = "";		if (month < 10) {			m = "0" + month;		} else {			m = month + "";		}		if (day < 10) {			d = "0" + day;		} else {			d = day + "";		}		return y + "-" + m + "-" + d;	}	/**	 * 从当前日期算起，获取N个月前的日期，日期格式为yyyy-MM-dd	 * 	 * @param mon 月份	 * @return	 */	public static String getDateByMonth(Integer mon) {		Date date = new Date();		int year = Integer.parseInt(new SimpleDateFormat("yyyy").format(date));		int month = Integer.parseInt(new SimpleDateFormat("MM").format(date)) - mon;		int day = Integer.parseInt(new SimpleDateFormat("dd").format(date));		if (month == 0) {			year -= 1;			month = 12;		} else if (day > 28) {			if (month == 2) {				if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {					day = 29;				} else {					day = 28;				}			} else if ((month == 4 || month == 6 || month == 9 || month == 11)					&& day == 31) {				day = 30;			}		}		String y = year + "";		String m = "";		String d = "";		if (month < 10) {			m = "00" + month;		} else {			m = month + "";		}		if (day < 10) {			d = "0" + day;		} else {			d = day + "";		}		return y + "-" + m + "-" + d;	}