java指定日期年月日加减法

	public static String dateAddYear(String date,String oriDateFormat,String targetDateFormat,int n) {
		
		if (StringUtils.isBlank(date) || StringUtils.isBlank(oriDateFormat) ||StringUtils.isBlank(targetDateFormat)) {
			return "";
		}
		
		SimpleDateFormat simpleDateFormat = new SimpleDateFormat(oriDateFormat);
		Date dateObj = null;
		try {
			dateObj = simpleDateFormat.parse(date);
		} catch (ParseException e) {
			return "";
		}
		
		Calendar cal = Calendar.getInstance();
		cal.setTime(dateObj);//设置起时间
		cal.add(Calendar.YEAR, n);//年份加法
		//cd.add(Calendar.MONTH, 3);//增加3个月
		//cd.add(Calendar.DATE, 10);//增加10天
   		//cd.add(Calendar.DATE, -20);//减20天    	
		SimpleDateFormat sdf = new SimpleDateFormat(targetDateFormat);
		String dateStr = sdf.format(cal.getTime());
		
        return dateStr;
	}