java日期时间操作

获取前一天的起始日期时间和结束日期时间:
如当前时间是2024-01-22,则返回2024-01-21 00:00:00,2024-01-21 11:59:59

		LocalDateTime now = LocalDateTime.now();
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        // 计算前一天的起始日期时间
        LocalDateTime startOfPreviousDay = now.minusDays(1).with(LocalTime.MIN);
        String formattedStartOfPreviousDay = startOfPreviousDay.format(formatter);
         System.out.println("前一天的起始日期和时间:" + formattedStartOfPreviousDay);
         
        // 计算前一天的结束日期时间
        LocalDateTime endOfPreviousDay = now.minusDays(1).with(LocalTime.MAX);
        String formattedEndOfPreviousDay = endOfPreviousDay.format(formatter);
        System.out.println("前一天的结束日期和时间:" + formattedEndOfPreviousDay);
        

转化当前String类型的日期时间到指定格式的String类型的日期(20240122):
如有当前String=“2024-01-22 17:30:15” => String=“20240122”

    public String toLocalDateString(String localDateTimeString) {
		DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        LocalDateTime localDateYesterDay = LocalDateTime.parse(localDateTimeString, formatter);
        String queryDayValue = localDateYesterDay.toLocalDate().format(DateTimeFormatter.ofPattern("yyyyMMdd"));
        }

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