时间格式转化_localdatetime 转 rfc3339-优快云博客

本文链接：https://blog.youkuaiyun.com/asdfghjklor/article/details/108253394

1 String 类型的"yyyy-MM-dd'T'HH:mm:ss"如何把T格式化。先转Date类型，在格式化date类型。

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
        SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        try {
            Date date = sdf.parse("2020-08-06T14:04:08");
            String dateTime = sdf2.format(date);
            log.info(dateTime);
        } catch (ParseException e) {
            e.printStackTrace();
        }

2 localdatetime的with方法，重新定义时间

        // localdatetime的with方法，重新定义时间
        LocalDateTime now = LocalDateTime.now();
        log.info(now.toString());
        LocalDateTime test = now.withHour(8).withMinute(9).withMonth(7);
        log.info(test.toString());

打印结果：2020-08-27T09:59:24.505
2020-07-27T08:09:24.505

3 insant

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
        // localdatetime获取当天北京时间
        LocalDateTime localDateTime = LocalDateTime.now();
        log.info("localdatetime获取当天北京时间:" + localDateTime.toString());
        // Instant获取当前时间为utc时间，比北京时间晚8个小时
        Instant instant = Instant.now();
        log.info("Instant 获取当前时间为utc时间，比北京时间晚8个小时:" + instant.toString());
        // Instant转换成北京时间
        Instant beijingInstant = instant.plusMillis(TimeUnit.HOURS.toMillis(8));
        log.info("Instant 转换成北京时间:" + beijingInstant.toString());
        // Instant 换换乘10位秒数和13位毫秒数
        Long second = instant.getEpochSecond();
        Long milli = instant.toEpochMilli();
        Long beijingmilli = beijingInstant.toEpochMilli();
        log.info("Instant 转换成10位秒数:" + second.toString());
        log.info("Instant 转换成和13位毫秒数:" + milli.toString());
        log.info("北京时间的instant:" + beijingmilli.toString());
        // localdatetime转换为long类型的毫秒(通过instant转成UTC时间的毫秒，比北京时间晚8小时)
        Long epochmilli = localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
        log.info("localdatetime转换为long类型的毫秒:" + epochmilli.toString());
        // localdatetime转换成instant
        Instant instant1 = localDateTime.toInstant(ZoneOffset.of("+8"));
        Instant instant2 = localDateTime.toInstant(ZoneOffset.ofHours(-8));
        log.info("localdatetime转换成instant 转换方式一:" + instant1);
        log.info("localdatetime转换成instant 转换方式二:" + instant2);
        // instant转换成Localdatetime 转换成系统默认时区
        LocalDateTime localDateTime1 = LocalDateTime.ofInstant(instant1, ZoneId.systemDefault());
        log.info("instant转换成Localdatetime:" + localDateTime1);
        // long转换为时间 long类型默认是utc的时间，转换成date自动+8
        Date date = new Date(beijingmilli);
        String dateString = sdf.format(date);
        log.info("long转换为时间:" + dateString);
        //influxdb取出的"yyyy-MM-dd'T'HH:mm:ss"转换为localdatetime
        String influxdbDate = "2020-08-27T08:00:00+08:00";
        DateTimeFormatter rfc3339 = new DateTimeFormatterBuilder()
                .appendPattern("yyyy-MM-dd'T'HH:mm:ss")
                .appendFraction(ChronoField.NANO_OF_SECOND, 0, 9, true)
                .appendZoneOrOffsetId().toFormatter();
        LocalDateTime dateTime = LocalDateTime.parse(influxdbDate, rfc3339);
        log.info("influxdb取出的\"yyyy-MM-dd'T'HH:mm:ss\"转换为localdatetime" + dateTime);

打印结果:

localdatetime获取当天北京时间:2020-08-27T16:23:29.289
Instant 获取当前时间为utc时间，比北京时间晚8个小时:2020-08-27T08:23:29.289Z
Instant 转换成北京时间:2020-08-27T16:23:29.289Z
Instant 转换成10位秒数:1598516609
Instant 转换成和13位毫秒数:1598516609289
北京时间的instant:1598545409289
localdatetime转换为long类型的毫秒:1598516609289
localdatetime转换成instant 转换方式一:2020-08-27T08:23:29.289Z
localdatetime转换成instant 转换方式二:2020-08-28T00:23:29.289Z
instant转换成Localdatetime:2020-08-27T16:23:29.289
long转换为时间:2020-08-28 00:23:29.289
influxdb取出的"yyyy-MM-dd'T'HH:mm:ss"转换为localdatetime2020-08-27T08:00