public static SimpleDateFormat yymmddFormat = new SimpleDateFormat("yyMMdd"); public static String getBeforeNDay(int n) { String datestr = ""; Date date = new Date(); date = new Date(date.getTime() - n*24 * 60 * 60 * 1000); datestr = yymmddFormat.format(date); return datestr; }
*gc.add(1,-1)表示年份减一.
*gc.add(2,-1)表示月份减一.
*gc.add(3.-1)表示周减一.
*gc.add(5,-1)表示天减一.
*以此类推应该可以精确的毫秒吧.没有再试.大家可以试试.
*GregorianCalendar类的add(int field,int amount)方法表示年月日加减.
*field参数表示年,月.日等.
*amount参数表示要加减的数量.
YEAR = 1
MONTH = 2
WEEK_OF_YEAR = 3
WEEK_OF_MONTH = 4
DATE = 5
DAY_OF_MONTH = 5
DAY_OF_YEAR = 6
DAY_OF_WEEK = 7
DAY_OF_WEEK_IN_MONTH = 8
AM_PM = 9
HOUR = 10MINUTE = 12
SECOND = 13
MILLISECOND = 14DST_OFFSET = 16
FIELD_COUNT = 17
new SimpleDateFormat("yyMMdd");
public static String getBeforeNDay(int n) {
String datestr = "";
Date date = new Date();
date = new Date(date.getTime() - n*24 * 60 * 60 * 1000);
datestr = yymmddFormat.format(date);
return datestr;
}