Java日期操作工具類

/**


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(減)後的那一天

@param date
@param num
(可正可負)
@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，因為Calendar里的月是從0開始，所以要減1
 cal.set(Calendar.DATE, 1);// 日，設為一號
 cal.add(Calendar.MONTH, 1);// 月份加一，得到下個月的一號
 cal.add(Calendar.DATE, -1);// 下一個月減一為本月最后一天
 return cal.getTime();// 獲得月末是幾號
}
/ */
/

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/
獲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 對于交叉:2008-12-29到2009-01-04屬于2008年的最后一周,2009-01-05為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 對于交叉:2008-12-29到2009-01-04屬于2008年的最后一周, 2009-01-04為
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;
}
/*獲取當前日期的年、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);
    }
}

}</pre>