JAVA 从 ISO_DATE_TIME 获取自纪元以来的毫秒数

Question

I'm trying to get Milliseconds since Epoch from ISO_DATE_TIME and i have been reading so many article.

My starting point is this: 2020-10-06T11:51:45.964+01:00

My ending point is a long that consider milliseconds. ( https://currentmillis.com/ )

I'm using a message coming from Kafka into Flink, and the time stamp is in the payload of the message.

This is my code:

public void setKafkaTime(String kafkaTime) {
    DateTimeFormatter sdr = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSXXXX");
    LocalDateTime MydateTime = LocalDateTime.parse(kafkaTime,sdr);
    NOT WORKING -> Date date = Date.from(MydateTime.toInstant(ZoneOffset.UTC));
    Long tn = date.getTime();
    this.time = tn;
}

There is so much about the topic and i tried many ways, starting from the Java doc:

https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#ISO_OFFSET_DATE_TIME But mine is not ISO-8601 standard as i have second and milliseconds.

i have been using some important tips from previous questions like this one, where i found the pattern Java string to date conversion and i got this nice table.

To use .getTime() I need a java.util.Date to convert LocalDateTime to Date I got in trouble with an error asking me for a Java.sql.Date.

I have been reading about the difference between the two, and from what I understood Java.sql doesn't consider the time, so I denfinetly should not use it.

java.util.Date vs java.sql.Date

I'm confident about the top two lines of the code, for the rest I'm struggling. I really can't get how to obtain a long. Any help would be really appreciated.

Thanks

Answer 1

Try this. I used a zoned time and then converted that to an instant to get the milliseconds.

public  void setKafkaTime(String kafkaTime) {
    DateTimeFormatter sdr = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSzzz");
    ZonedDateTime MydateTime = ZonedDateTime.parse(kafkaTime,sdr);
    this.time = MydateTime.toInstant().toEpochMilli();
}