Java日期操作工具类
jopen
11年前
/** * java日期操作(月末、周末等的日期操作) * * @author * */ public class DateUtil { /** */ /** * 取得某天相加(减)後的那一天 * * @param date * @param num * (可正可负) * @return */ public static Date getAnotherDate(Date date, int num) { Calendar c = Calendar.getInstance(); c.setTime(date); c.add(Calendar.DAY_OF_YEAR, num); return c.getTime(); } /** */ /** * 取得某月的的最后一天 * * @param year * @param month * @return */ public static Date getLastDayOfMonth(int year, int month) { Calendar cal = Calendar.getInstance(); cal.set(Calendar.YEAR, year);// 年 cal.set(Calendar.MONTH, month - 1);// 月，因为Calendar里的月是从0开始，所以要减1 cal.set(Calendar.DATE, 1);// 日，设为一号 cal.add(Calendar.MONTH, 1);// 月份加一，得到下个月的一号 cal.add(Calendar.DATE, -1);// 下一个月减一为本月最后一天 return cal.getTime();// 获得月末是几号 } /** */ /** * 取得某天是一年中的多少周 * * @param date * @return */ public static int getWeekOfYear(Date date) { Calendar c = new GregorianCalendar(); c.setFirstDayOfWeek(Calendar.MONDAY); c.setMinimalDaysInFirstWeek(7); c.setTime(date); return c.get(Calendar.WEEK_OF_YEAR); } /** */ /** * 取得某天所在周的第一天 * * @param date * @return */ public static Date getFirstDayOfWeek(Date date) { Calendar c = new GregorianCalendar(); c.setFirstDayOfWeek(Calendar.MONDAY); c.setTime(date); c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); return c.getTime(); } /** */ /** * 取得某天所在周的最后一天 * * @param date * @return */ public static Date getLastDayOfWeek(Date date) { Calendar c = new GregorianCalendar(); c.setFirstDayOfWeek(Calendar.MONDAY); c.setTime(date); c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); return c.getTime(); } /** */ /**http://ini.iteye.com/ * 取得某一年共有多少周 * * @param year * @return */ public static int getMaxWeekNumOfYear(int year) { Calendar c = new GregorianCalendar(); c.set(year, Calendar.DECEMBER, 31, 23, 59, 59); return getWeekOfYear(c.getTime()); } /** * http://ini.iteye.com/ * 获取某一年某一周的日期 * @description * @param year * @param week * @return */ public static List<String> getWeekDays(int year,int week){ List<String> list = new ArrayList<String>(); Date date = getFirstDayOfWeek(year,week); SimpleDateFormat d = new SimpleDateFormat("yyyy-MM-dd"); for (int i = 0; i < 7; i++) { list.add(d.format(date)); System.out.println(d.format(date)); date.setDate(date.getDate()+1); } return list; } /** */ /** * 取得某年某周的第一天 对于交叉:2008-12-29到2009-01-04属于2008年的最后一周,2009-01-05为2009年第一周的第一天 * * @param year * @param week * @return */ public static Date getFirstDayOfWeek(int year, int week) { Calendar calFirst = Calendar.getInstance(); calFirst.set(year, 0, 7); Date firstDate = getFirstDayOfWeek(calFirst.getTime()); Calendar firstDateCal = Calendar.getInstance(); firstDateCal.setTime(firstDate); Calendar c = new GregorianCalendar(); c.set(Calendar.YEAR, year); c.set(Calendar.MONTH, Calendar.JANUARY); c.set(Calendar.DATE, firstDateCal.get(Calendar.DATE)); Calendar cal = (GregorianCalendar) c.clone(); cal.add(Calendar.DATE, (week - 1) * 7); firstDate = getFirstDayOfWeek(cal.getTime()); return firstDate; } /** */ /** * 取得某年某周的最后一天 对于交叉:2008-12-29到2009-01-04属于2008年的最后一周, 2009-01-04为 * 2008年最后一周的最后一天 * * @param year * @param week * @return */ public static Date getLastDayOfWeek(int year, int week) { Calendar calLast = Calendar.getInstance(); calLast.set(year, 0, 7); Date firstDate = getLastDayOfWeek(calLast.getTime()); Calendar firstDateCal = Calendar.getInstance(); firstDateCal.setTime(firstDate); Calendar c = new GregorianCalendar(); c.set(Calendar.YEAR, year); c.set(Calendar.MONTH, Calendar.JANUARY); c.set(Calendar.DATE, firstDateCal.get(Calendar.DATE)); Calendar cal = (GregorianCalendar) c.clone(); cal.add(Calendar.DATE, (week - 1) * 7); Date lastDate = getLastDayOfWeek(cal.getTime()); return lastDate; } /** *获取当前日期的年、月、日 */ public void display() { Calendar cal = Calendar.getInstance(); // 年 int year = cal.get(cal.YEAR); // 月 int month = cal.get(cal.MONTH) + 1; // 日 int date = cal.get(cal.DATE); // 星期 int today = cal.get(cal.DAY_OF_WEEK) - 1; } public static void main(String args[]){ List<String> listWeekDate = DateUtil.getWeekDays(2010,52); for(String weeks :listWeekDate){ System.out.println("weeks:"+weeks); } } }