获取哪一年 周一的所有日期

        WeekFields weekFields= WeekFields.ISO;

        int num = LocalDate.of(2020, 12, 31).get(weekFields.weekOfWeekBasedYear());
        //一年最后一天日期的LocalDate，如果该天获得的周数为1或52，那么该年就只有52周，否则就是53周
        num = (num == 1 || num==52) ? 52 : num;
        System.out.println("共有多少个周"+num);
        LocalDate now = LocalDate.now();
        List timeSum=new ArrayList<>();
        for (int i = 1; i <=num; i++)
        {
            //输入你想要的年份和周数
            LocalDate localDate = now.withYear(2020).with(weekFields.weekOfYear(),i);
            //周一
            LocalDate localDate1  = localDate.with(weekFields.dayOfWeek(), 1L);
            timeSum.add(localDate1);
            //周日
            LocalDate localDate2  = localDate.with(weekFields.dayOfWeek(), 7L);

        }
        System.out.println(timeSum);