两个日期相减（不包括日在内），得到差值 即相差多少个月

public class Test {
public static void main (String[] args) throws Exception {
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
System.out.println (getMonthNum(format.parse("2009-1-1"), format.parse("2010-1-31")));
System.out.println (getMonthNum(format.parse("2009-1-1"), format.parse("2009-1-31")));
System.out.println (getMonthNum(format.parse("2009-1-1"), format.parse("2009-6-2")));
System.out.println (getMonthNum(format.parse("2009-1-1"), format.parse("2008-1-31")));
}
public static int getMonthNum(Date date1,Date date2) {
Calendar cal1=Calendar.getInstance();
cal1.setTime(date1);
Calendar cal2=Calendar.getInstance();
cal2.setTime(date2);
return (cal2.get(1)-cal1.get(1))*12+(cal2.get(2)-cal1.get(2));
}
}