Java 日期按月拆分周

最新推荐文章于 2023-09-24 23:42:44 发布

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最新推荐文章于 2023-09-24 23:42:44 发布

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分类专栏： util java 文章标签： java 开发语言

本文链接：https://blog.youkuaiyun.com/qq_34346915/article/details/122169416

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1.严格按照所在月份拆分

   /**
     *严格按照所在月份拆分
     * @param startDate 2021-12
     * @return
     */
    public static List<String>  getWeekDay(String startDate) {
      
        LocalDate date = LocalDate.parse(startDate+"-01");
        // 该月第一天
        LocalDate firstDay = date.with(TemporalAdjusters.firstDayOfMonth());
        // 该月最后一天
        LocalDate lastDay = date.with(TemporalAdjusters.lastDayOfMonth());
        // 该月的第一个周一
        LocalDate start = date.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));
        List<String> list = new ArrayList<>();
        // 处理每个月的1号不是周一的情况
        if (!firstDay.equals(start)) {
            StringBuilder strbur = new StringBuilder();
            strbur.append(firstDay.toString()).append("~").append(start.plusDays(-1).toString());
            list.add(strbur.toString());
        }
        while (start.isBefore(lastDay)) {
            StringBuilder strbur = new StringBuilder();
            strbur.append(start.toString());
            LocalDate temp = start.plusDays(6);
            if (temp.isBefore(lastDay)) {
                strbur.append("~").append(temp.toString());
            } else {
                strbur.append("~").append(lastDay.toString());
            }
            list.add(strbur.toString());
            start = start.plusWeeks(1);
        }
       return list;
    }

2.不严格按照月份拆分（跨月时将上月日期算到下月的第一周）

 /**
     * 不严格按照月份拆分（跨月时将上月日期算到下月的第一周）
     * @param startDate 2021-12
     * @return
     */
    public static List<String> getWeekDay(String startDate) {
        // Java8  LocalDate
        LocalDate date = LocalDate.parse(startDate + "-01");
        // 该月第一天所在周的 周一
        LocalDate firstDay=date.with(TemporalAdjusters.previous(java.time.DayOfWeek.SUNDAY)).plusDays(1);

        // 该月的第一个周一
        LocalDate start = date.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));

        // 该月的最后一个周日
        LocalDate lastDay = date.with(TemporalAdjusters.lastInMonth(DayOfWeek.SUNDAY));

        List<String> list = new ArrayList<>();
        // 处理每个月的1号不是周一的情况
        if (!firstDay.equals(start)) {
            LocalDateToUdate();
            StringBuilder strbur = new StringBuilder();
            strbur.append(firstDay.toString()).append("~").append(start.plusDays(-1).toString());
            list.add(strbur.toString());
        }
        while (start.isBefore(lastDay)) {
            StringBuilder strbur = new StringBuilder();
            strbur.append(start.toString());
            LocalDate temp = start.plusDays(6);
            if (temp.isBefore(lastDay)) {
                strbur.append("~").append(temp.toString());
            } else {
                strbur.append("~").append(lastDay.toString());
            }
            list.add(strbur.toString());
            start = start.plusWeeks(1);
        }
        return list;
    }