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Spring Boot 2 get client timezone [duplicate]

How to get client/request timezone in jsp?

Unfortunately this information is not passed in HTTP headers.
Usually you need cooperating JavaScript to fetch it for you.
Web is full of examples, here is one http://www.coderanch.com/t/486127/JSP/java/Query-timezone

you cannot get timezone, but you can get current time from client side.i.e. through javascript and than post back. On server side, you can convert that time to GMT/UTC. The UTC shows the TimeZone.

If you just need the local timezone in order to display local times to the user, I recommend representing all times in your service in UTC and rendering them in browsers as local times using Moment.js.
My general rule is to handle and store times in UTC everywhere except at the interface with the user, where you convert to/from local time. The advantage of UTC is that you never have to worry about daylight-saving adjustments.
Note that if you want to show the age of something (e.g. "posted 3 hours ago") you just need to compare the UTC timestamp with the current UTC time; no need to convert to local times at all.

Best solution for me is sending date/time as a string, and then parse with server's timezone to get a timestamp. Timestamps are always UTC (or supposed to be) so you will not need client's TimeZone.
For example, sending "10/07/2018 12:45" can be parsed like:
SimpleDateFormat oD = new SimpleDateFormat();
oD.applyPattern("dd/MM/yyyy HH:mm");
oD.setTimeZone(TimeZone.getDefault()); // ;)
Date oDate = oD.parse(request.getParameter("time"));
Obviously you can set your specific date/time format.

EDT or EST? Dynamically set 3 letter timezone based on daylight savings

Given a timezone like 'EDT' in java, is there a way to set an arbitrary datetime in java to be in that timezone and print with the correct label, (either EDT or EST)?
Some context:
I am developing a weekly report generation feature that needs to timestamp reports in the timezone of the user who first configured the report. I would like to label the reports using the 3 letter timezone labels like 'EST' or 'CST,' so that users would see a message like "This report was generated at 03-28-2018 12:00:00 pm EDT." (I realize these can be ambiguous.)
Reports are generated as pdfs on the server so all information must come from the report configuration saved in the database.
Right now when the client posts a new report configuration, it includes the three letter timezone in the configuration along with its offset (eg 'GMT-0400' for EDT), and use that to create a LocalDateTime with the saved offset, then print it with saved label. Obviously this won't account for daylight savings, so I need a better solution.
For reference I am using AngularJS on the client.

It turns out my problem needed a client side solution, based on comments and this question, I used moment.js moment.tz.guess(); to get an IANA timezone which is included when configuring a new report.
Once the server knows the IANA timezone creating the zoned datetime is simple:
String timezone = "America/New_York";
ZonedDateTime timestamp = ZonedDateTime.now().withZoneSameInstant(ZoneId.of(timezone));

vertex 3.x fetch timezone from http request

I am using vertex 3.x. I have a requirement to access timezone from HttpServerRequest object to provide timezone based data to user.

It doesn't have one, basically. There's nothing in a regular HTTP request to identify the time zone.
Your options are:
Use an IP geocoding API to guess at the user's location, followed by a location-to-timezone conversion (e.g. through another API)
Use Javascript to detect the time zone - there are various libraries available to do this, usually resulting in an IANA time zone ID such as "Europe/London"
Probably in conjunction with the first two, offer the users a choice so they can confirm their actual time zone
Note that detecting location from IP address can be fraught with issues due to proxies which are often employed by large corporations.
Also note that even once you've got the same time zone ID as the browser, it's entirely possible that your copy of time zone data on the server will be different to the time zone data in the browser - it changes reasonably regularly. (You'd be fairly unlucky to hit a problem, so long as you keep your data up-to-date, but you should be aware of it.)

Java gregorian calendar and removing time and timezone

I have a gregorian calendar that serializes to the string below during a soap request
2079-07-07T00:00:00.000-07:00
The .NET webservice reads it as the string below
07/07/2079 01:00:00
Is the 07:00 causing the issue? If so how can I get rid of this?

Someone might be able to give you an affirmative answer if you tell us which time zone is configured on your system, but I would assume a mismatch in the DST rules.
The JVM comes with its own timezone and DST rule database, while Windows (and .NET) uses a different database. In theory, the two databases should of course contain the same rules, but I have ran into differences in the DST rules for historical dates. I would assume there might be differences for dates far in the future as well.
If you actually want to transport a date value (no time component) over the SOAP service, the easiest solution would be to use the appropriate XML Schema datatype instead of a datetime type.

Use a DateTimeOffset in your .net code and it will work just fine.

Weird mysql beahviours with timezones? How to control them?

I wrote a webapp using spring+hibernate. I developed everything on windows and then I moved it to a Linux virtual server (Aruba, an Italian provider). I noticed an annoying thing: when dates where saved on windows the time would be the same of my "wall clock", so if I read 13:45 I will have the same hour in the mysql row. This doesn't happen on Linux anyway. In fact the linux machine is on CEST as well (my timezone), I got it typing "date" in the shell. But I get the dates saved in the DB with an offset that is relative to GMT. Again, my app always displays everything in GMT (Including GMT as a time zone if I choose to format the dates to display the time zone) and mysql saves everything in that format. How do I control all this?

I post the solution by myself, because I think it's worth having it in this site.
First of all: mySql doesn't store any timezone information. So say that you are running on GMT+4 and you write a couple of records that contain date fields. Then you move your system in GMT-2 you read those records (perhaps importing the data from mysqldump). If your system and VM have GMT-2 as timezone the dates you read will be taken as if they were written in GMT-2 and NOT ADJUSTED.
Solution: Take control of your VM timezone by using -Duser.timezone="GMT" command line option (you can even put this in your Tomcat startup script) or your preferred timezone (but GMT is better, let me explain why). This way you'll know for sure which timezone your VM is running. This doesn't mean that Java VM will assume that your system time is the one you specified in your user.timezone, it will know the system timezone and adjust dates accordingly. In fact if you are not in GMT, you will see dates in adjusted to GMT and saved to DB accordingly. This way you'll be sure that you are using that as a reference.
The problem is that if you take a date object and you do myDateObject.toString(), you'll get the date adjusted to GMT, with the hour offset. Which is not what you'll probably want.
The solution is to use SimpleDateFormat and do somthing like this when you have to output a date:
SimpleDateFormat dateFormat = new SimpleDateFormat(
"HH:mm dd/MM/yyyy z", Locale.ITALY);
dateFormat.setTimeZone(TimeZone.getTimeZone("Europe/Rome"));
Everything will get converted the right way. You can even go further if you are developing a web app. You can extract the timezone from the HttpRequest and adjust date output accordingly, but I didn't go so far as I'm writing an application that is intended for Italian users only :D (yay).
Hope this will help.