获取某年N周变异量后年周列表以及某个周对应开始结束日期

逛别人博客改自己代码，我只是个代码搬运工，用到业务场景获取当年后4周的周数，以及选择其中某个周获取周对应开始结束日期，通业务场景网上找代码麻烦，所以方便其他兄弟，贴出全部代码如下：

public class WeekUtils {

public static void main(String[] args)

{

System.out.println(getWeekAndYear("2020-06-16"));

System.out.println(getStartDayOfWeekNo(2020,53));

System.out.println(getEndDayOfWeekNo(2020,53));

getWeeksAndYear(2020,25,1);

getWeeksAndYear("2020-12-31",4);

System.out.println(getDateByYearweek("20212"));

}

/**

* 当前日期所在一年中的第几周

* @param date

* @return

public static MapgetWeekAndYear(String date) {

Map result =new HashMap();

Calendar cal = Calendar.getInstance();

//设置一周的开始,默认是周日,这里设置成星期一

cal.setFirstDayOfWeek(Calendar.MONDAY);

SimpleDateFormat format =new SimpleDateFormat("yyyy-MM-dd");

SimpleDateFormat formatMon =new SimpleDateFormat("MM");

SimpleDateFormat formatYear =new SimpleDateFormat("yyyy");

Date d =null;

try {

d = format.parse(date);

}catch (ParseException e) {

e.printStackTrace();

}

cal.setTime(d);

int month = Integer.valueOf(formatMon.format(d));

int year = Integer.valueOf(formatYear.format(d));

int week = cal.get(Calendar.WEEK_OF_YEAR);

result.put("week", week);

if(week ==1 && month ==12){

result.put("year", year +1);

}else{

result.put("year", year);

}

return result;

}

/**

* 某个日期所在年周偏移量是指获取多少个年周

* @param date

* @param offset

* @return

public static ListgetWeeksAndYear(String date, int offset) {

if(StringUtils.isBlank(date))

{

date = DateUtils.format(new Date());

}

Calendar cal = Calendar.getInstance();

//设置一周的开始,默认是周日,这里设置成星期一

cal.setFirstDayOfWeek(Calendar.MONDAY);

SimpleDateFormat format =new SimpleDateFormat("yyyy-MM-dd");

SimpleDateFormat formatMon =new SimpleDateFormat("MM");

SimpleDateFormat formatYear =new SimpleDateFormat("yyyy");

Date d =null;

try {

d = format.parse(date);

}catch (ParseException e) {

e.printStackTrace();

}

cal.setTime(d);

int month = Integer.valueOf(formatMon.format(d));

int year = Integer.valueOf(formatYear.format(d));

int week = cal.get(Calendar.WEEK_OF_YEAR);

if(week ==1 && month ==12){

year = year +1;

}

Calendar cal1 =getCalendarFormYear(year);

List ywList =new ArrayList<>();

for(int i =1 ;i<= offset;i++)

{

cal1.set(Calendar.WEEK_OF_YEAR, week + i);

int jsweek = cal1.get(Calendar.WEEK_OF_YEAR);

int jsyear = cal1.get(Calendar.YEAR);

//System.out.println("item:"+jsyear+""+jsweek);

String sjyw = jsyear+""+jsweek;

ywList.add(sjyw);

}

return ywList;

}

/**

* 根据年周查询对应的周一和周日的日期

* @param yearweek

* @return

public static ListgetDateByYearweek(String yearweek){

String year = yearweek.substring(0,4);

String weekno = yearweek.substring(4,yearweek.length());

List dateList =new ArrayList<>();

String startDateStr =getStartDayOfWeekNo(Integer.parseInt(year),Integer.parseInt(weekno));

String endDateStr =getEndDayOfWeekNo(Integer.parseInt(year),Integer.parseInt(weekno));

dateList.add(startDateStr);

dateList.add(endDateStr);

return dateList;

}

/**

* 获取某年某周后多少周是第几周

* @param year

* @param weekno

* @param offset

public static void getWeeksAndYear(int year, int weekno, int offset) {

Calendar cal =getCalendarFormYear(year);

cal.set(Calendar.WEEK_OF_YEAR, weekno + offset);

int week = cal.get(Calendar.WEEK_OF_YEAR);

int jsyear = cal.get(Calendar.YEAR);

System.out.println(jsyear+""+week);

}

/**

* get Calendar of given year

* @param year

* @return

private static CalendargetCalendarFormYear(int year){

Calendar cal = Calendar.getInstance();

cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);

cal.set(Calendar.YEAR, year);

return cal;

}

/**

* get start date of given week no of a year

* @param year

* @param weekNo

* @return

public static StringgetStartDayOfWeekNo(int year,int weekNo){

Calendar cal =getCalendarFormYear(year);

cal.set(Calendar.WEEK_OF_YEAR, weekNo);

return cal.get(Calendar.YEAR) +"-" + (cal.get(Calendar.MONTH) +1) +"-" +

cal.get(Calendar.DAY_OF_MONTH);

}

/**

* get the end day of given week no of a year.

* @param year

* @param weekNo

* @return

public static StringgetEndDayOfWeekNo(int year,int weekNo){

Calendar cal =getCalendarFormYear(year);

cal.set(Calendar.WEEK_OF_YEAR, weekNo);

cal.add(Calendar.DAY_OF_WEEK, 6);

return cal.get(Calendar.YEAR) +"-" + (cal.get(Calendar.MONTH) +1) +"-" +

cal.get(Calendar.DAY_OF_MONTH);

}