SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");
java.util.Date date= myFormatter.parse("2003-12-1");
java.util.Date mydate= myFormatter.parse("2001-12-1");
day=(date.getTime()-mydate.getTime())/(24*60*60*1000);
int month=(int)(day/30);
out.println(month);
out.println("<br>");
java.util.Date date= myFormatter.parse("2003-12-1");
java.util.Date mydate= myFormatter.parse("2001-12-1");
day=(date.getTime()-mydate.getTime())/(24*60*60*1000);
int month=(int)(day/30);
out.println(month);
out.println("<br>");
java.util.Date myDate=new java.util.Date();
long myTime=(myDate.getTime()/1000)-60*24*60*365;
myDate.setTime(myTime*1000);
String mDate=formatter.format(myDate);
out.println(mDate);
out.println("<br>");
SimpleDateFormat format = new SimpleDateFormat("yyyyMM");
Date date = format.parse(str);
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("CTT"));
calendar.setTime(date);
calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH)-24);//前24个月
System.out.println(format.format(calendar.getTime()));
calendar.add(Calendar.MONTH,-24);//减去24月。