获取给定年月，当月有几周，每周开始结束日期

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package date;   import java.time.LocalDate; import java.time.format.DateTimeFormatter; import java.time.temporal.TemporalAdjusters; import java.util.ArrayList; import java.util.Calendar; import java.util.HashMap; import java.util.List; import java.util.Map; /**  * 获取给定年月计算当月有几周，每周的开始和结束日期  * @author pei  *  */   public class TestLocal {     static DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");           public static void main(String[] args) {                   List<Map> list =  getScope();         System.out.println("list====="+list);         }                 public static List<Map> getScope() {         String date = "2023-01-01";         String timeStrs[] = date.split("-");         Calendar c = Calendar.getInstance();         c.set(Calendar.YEAR, Integer.parseInt(timeStrs[0]));         c.set(Calendar.MONTH, Integer.parseInt(timeStrs[1]) - 1);         c.setFirstDayOfWeek(Calendar.MONDAY);         int weeks = c.getActualMaximum(Calendar.WEEK_OF_MONTH);           LocalDate localDateate = LocalDate.parse(date, dateTimeFormatter);         //月份第一周的起始时间和结束时间         LocalDate firstDay = localDateate.with(TemporalAdjusters.firstDayOfMonth());         String firstDayStr = firstDay.format(dateTimeFormatter);         String sunStr = getSunOfWeek(firstDayStr);           List<Map> weekInfos = new ArrayList<>();         for (int i = 1; i <= weeks; i++) {             Map weekInfo = new HashMap();             //第一周的起始时间就是当月的1号，结束时间就是周日             if (i == 1) {                 weekInfo.put("start",firstDayStr);                 weekInfo.put("end",sunStr);                 weekInfo.put("order",i);                 //计算接下来每周的周一和周日             } else if (i < weeks) {                 //由于sunStr是上一周的周日，所以取周一要取sunStr的下一周的周一                 String monDay = getLastMonOfWeek(sunStr);                 sunStr = getSunOfWeek(monDay);                 weekInfo.put("start",monDay);                 weekInfo.put("end",sunStr);                 weekInfo.put("order",i);                 //由于最后一周可能结束时间不是周日，所以要单独处理             } else {                 String monDay = getLastMonOfWeek(sunStr);                 //结束时间肯定就是当前月的最后一天                 LocalDate lastDay = localDateate.with(TemporalAdjusters.lastDayOfMonth());                 String endDay = lastDay.format(dateTimeFormatter);                 weekInfo.put("start",monDay);                 weekInfo.put("end",endDay);                 weekInfo.put("order",i);             }               weekInfos.add(weekInfo);           }         return weekInfos;     }           //算出所在周的周日     public static String getSunOfWeek(String time) {         LocalDate localDateate = LocalDate.parse(time, dateTimeFormatter);         LocalDate endday = localDateate.with(TemporalAdjusters.next(java.time.DayOfWeek.MONDAY)).minusDays(1);         String endDayStr = endday.format(dateTimeFormatter);         return endDayStr;     }       //下一周的周一     public static String getLastMonOfWeek(String time) {         LocalDate localDateate = LocalDate.parse(time, dateTimeFormatter);         LocalDate endday = localDateate.with(TemporalAdjusters.next(java.time.DayOfWeek.MONDAY));         String endDayStr = endday.format(dateTimeFormatter);         return endDayStr;     }   }