java1.8LocalDateTime学习

        //获取当前时间    2022-07-26T21:44:45.672
        LocalDateTime now = LocalDateTime.now();
        log.info("当前时间为:" + now);
        //格式化时间 2022年07月26日21时47分04秒
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy年MM月dd日HH时mm分ss秒");
//        dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        log.info(dateTimeFormatter.format(now));
        LocalDateTime parse = LocalDateTime.parse(dateTimeFormatter.format(now), dateTimeFormatter);
        log.info("字符串转为时间:" + parse);
        //21
        log.info("当前时间的小时为:" + now.getHour());
        //获取当前纳秒值   367000000
        log.info("当前时间的纳秒值为:" + now.getNano());
        //2022-07-26T22:02:15.099+08:00[Asia/Shanghai]
        log.info("获取系统所属时区以及当前时间:" + now.atZone(ZoneId.systemDefault()));
        //26
        log.info("获取指定单位的时间:" + now.get(ChronoField.DAY_OF_MONTH));
        log.info("判断两个时间的先后顺序:当前时间是否在指定时间之后->" + now.isAfter(LocalDateTime.now()));
        log.info("判断两个时间的先后顺序:当前时间是否在指定时间之前->" + now.isBefore(LocalDateTime.now()));
        log.info("判断两个时间是否相同时刻:->" + now.isEqual(LocalDateTime.now()));
        //当前时间比指定时间小则返回-1,大则返回1,相等则返回0
        log.info("比较两个时间点的大小:"+now.compareTo(LocalDateTime.now()));
        //localdatetime 转为localdate
        log.info("当前时间为:" + now.toLocalDate());
        log.info("LocalDateTime to Date:" + Date.from(now.atZone(ZoneId.systemDefault()).toInstant()));
        log.info("1.Date to LocalDateTime:" + LocalDateTime.ofInstant(Instant.ofEpochMilli(new Date().getTime()), ZoneOffset.ofHours(8)));
        log.info("2.Date to LocalDateTime:" + new Date().toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime());
        log.info("当前时间加一天之后的时间:" + now.plusDays(1));
        log.info("当前时间加指定数量,指定单位后的时间:" + now.plus(2L, ChronoUnit.WEEKS));
        log.info("当前时间减指定数量,指定单位后的时间:" + now.minus(2L, ChronoUnit.DAYS));