How to convert Timestamp in CDT Format to MM/DD in Java?

Question

I have a timestamp in cdt format as below "2023-06-05T09:00:01CDT", I want to convert this timestamp into MM/DD format in Java.

I have tried below : The expected output was: 6/5 But was getting parsing error.

ZonedDateTime ztime = ZonedDateTime.parse("2023-06-05T09:00:01CDT");
Date date = Date.from(Instant.from(ztime));
Calendar cal = Calendar.getInstance();
cal.setTime(date);
return (cal.get(Calendar.MONTH) + 1) + "/" + cal.get(Calendar.DATE);

Stack trace:

Exception in thread "main" java.time.format.DateTimeParseException: Text '2023-06-05T09:00:01CDT' could not be parsed at index 19
    at java.base/java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:2056)
    at java.base/java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1958)
    at java.base/java.time.ZonedDateTime.parse(ZonedDateTime.java:600)
    at java.base/java.time.ZonedDateTime.parse(ZonedDateTime.java:585)
    at MyClass.main(MyClass.java:9)

What is *no luck* exactly supposed to mean? Compile error? Program crash? Unexpected output? — deHaar, Jun 05 '23 at 12:59
The parsing error comes because `CDT` is no `ZoneId`, it is an (old fashioned) `TimeZone` and you are implicitly using a `DateTimeFormatter` that expects a `ZoneId`, like `"Europe/Amsterdam"`; — deHaar, Jun 05 '23 at 13:12
If you want that month-day pattern as is *in the original*, without worrying about the offset, you can maybe treat it as a `LocalDateTime`: e.g. `String MMdd = LocalDateTime.parse(s.replace("CDT", "")).format(DateTimeFormatter.ofPattern("MM/dd"));` Of course it then no longer is an accurate `Instant` and the date might be 'wrong' wrt that `Instant` — g00se, Jun 05 '23 at 13:27
First of all: **Do not** use `Calendar` and `Date`. java.time, the modern Java date and time API from which you took `ZonedDateTime` has got all the functionality that you need, so both to avoid an unnecessary conversion and to avoid the trouble with the poorly deisgned and outdated `Date` and `Calendar` classes. Use two `DateTimeFormatter` objects, one for parsing and one for formatting. — Ole V.V., Jun 05 '23 at 14:46
It may not be important, but by CDT did you mean Australian Central Daylight Time, North American Central Daylight Time, Cuba Daylight Time, Chatham Daylight Time or something else? More importantly, though, do you want the month in the same time zone? Near the end and beginning of a month it matters. — Ole V.V., Jun 05 '23 at 14:49

deHaar · Answer 1 · 2023-06-05T15:03:23.883

4

If you simply want to parse a full ZonedDateTime String representation that includes a time zone (three letters) instead of a standard zone id, you will have to prepare a formatter for it.

Having successfully parsed that String, the quickest way to get a String of the format "MM/dd" would be to use the method format(DateTimeFormatter) of ZonedDateTime and define the pattern to only output month-of-year and day-of-month…

example code

public static void main(String[] args) {
    // example input
    DateTimeFormatter dtf = DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ssz");
    // prepare a formatter that can actually parse the String with a time zone
    ZonedDateTime ztime = ZonedDateTime.parse("2023-06-05T09:00:01CDT", dtf);
    // print the full zoned date time
    System.out.println(ztime);
    // and print the result in a format that only considers month of year and day of month
    System.out.println(ztime.format(DateTimeFormatter.ofPattern("M/d")));
}

Output

2023-06-05T09:00:01-05:00[America/Chicago]
6/5

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very short solution
uses only one API, the modern one…

edited Jun 05 '23 at 15:03

answered Jun 05 '23 at 13:24

deHaar

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Actually, for me, it outputs: *2023-06-05T09:00:01+08:00[Asia/Shanghai]* – g00se Jun 05 '23 at 13:39
1

That's one of the dangerous things about the three-letter time zones, they are ambiguous. Obviously, your jvm/machine assumes `CDT` is not `Central Daylight Saving Time`, but anything different. Could be `Cuba Daylight Saving Time` or `China Daylight Saving Time`… The latter would explain `"Asia/Shanghai"`. – deHaar Jun 05 '23 at 13:43
Alternative means of generating a month/day string: `String.format("%tm/% – VGR Jun 05 '23 at 13:47
I think the CDT must be *discarded*, not processed – g00se Jun 05 '23 at 14:37
That may be an option in this situation, but not generally… – deHaar Jun 05 '23 at 14:47
1

@g00se That depends a lot. Best of course if we can avoid dealing with ambiguous data and the risk of of interpreting it wrong. If I can, I will still prefer to make sure what was meant by CDT and process it according to that. Then I’m prepared the day business happens to think they wanted the month in UTC or some other time zone. If we opt to avoid using the ambiguous time zone abbreviation, the solution is to parse into a `LocalDateTime` instead of a `ZonedDateTime` thus effectively discarding the information (and crossing our fingers that it wasn’t vital in this particular case). – Ole V.V. Jun 05 '23 at 14:55
Yes. If you look above, that was what I suggested doing as a possibility ;) – g00se Jun 05 '23 at 14:58

Aliana · Answer 2 · 2023-06-08T07:55:59.027

This might be helpful.

        String cdtTimestamp = "2023-06-01T15:30:00-05:00"; // Example CDT timestamp
        // Parse CDT timestamp into ZonedDateTime
        ZonedDateTime cdtDateTime = ZonedDateTime.parse(cdtTimestamp);
        // Convert to local timezone (optional)
        ZonedDateTime localDateTime = cdtDateTime.withZoneSameInstant(ZoneId.systemDefault());
        // Format the date as MM/DD
        DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("MM/dd");
        String formattedDate = localDateTime.format(dateFormatter);
        System.out.println("Formatted date: " + formattedDate);

Thank you for the feedback. I appreciate the opportunity to contribute and learn as a beginner. — Aliana, Jun 06 '23 at 10:47

score 1 · Accepted Answer · answered Jun 05 '23 at 13:11

1

Try this code snippet, if it is a parsing issue you can add a DateTimeFormatter :: documentation

    DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssz");
    ZonedDateTime time = ZonedDateTime.parse("2023-06-05T09:00:01CDT", format);
    Date date = Date.from(Instant.from(time));
    cal.setTime(date);
    Calendar cal = Calendar.getInstance();
    String date =  (cal.get(Calendar.MONTH) + 1) + "/" + cal.get(Calendar.DATE);

answered Jun 05 '23 at 13:11

Gokul G.K

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Yeah this is helpful – BugEater Jun 05 '23 at 13:13
3

This is better than nothing, but that's it. I wouldn't call this helpful because it is mixing outdated and modern APIs as well as it is doing unnecessary conversions, even a lot of them! – deHaar Jun 05 '23 at 13:14
1

In addition to what @deHaar said, picking fields out of a `Calendar` object and remembering to add 1 because of`Calendar`’s senseless month numbering is a bad way to format a date, even though it was also used in the question. One should use a second formatter. – Ole V.V. Jun 05 '23 at 15:16
2

But this statement is helpful: *if it is a parsing issue you can add a DateTimeFormatter*. And the documentation link is. – Ole V.V. Jun 05 '23 at 15:25

How to convert Timestamp in CDT Format to MM/DD in Java?

3 Answers3

example code

Output

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