获取两个日期之间的年限差

/**
 * 获取两个时间的年限差
 * 
 * @param preDate
 * @param afterDate
 * @return
 */
public static int getYearsByTowDate(Date preDate, Date afterDate) {
	if (afterDate == null) {
		afterDate = new Date();
	}
	int years = Math.abs(afterDate.getYear() - preDate.getYear());
	years = years > 0 ? years - 1 : 0;
	return years;
}