I have to format date/time in my gwt app with specific timezone, which is loaded from the server. Possible timezones are like this GMT, GMT+1, GMT-2 etc...
Up to now i used DateTimeFormat to format my timestamps, and they used client's locale.
PLease help.
You can format in any timezone you want with DateTimeFormat, you just have to pass it as the second argument to the format method.
And to obtain a TimeZone object, depending on how you want to present the timezone information (if ever) in the formatted date/time, you can use either createTimeZone(int) or createTimeZone(String) (getting the string out of TimeZoneConstants).
Related
How to use to_date function in oracle-sqldeveloper to convert a string
May 1 2019 12:00 to date datatype? Does Date in SQL store time too,
or it only stores date? I tried using the to_date function with some
format but it always removes the time part.
If the time is not possible in Date datatype what could be a good alternative?
You can convert your date to a string with (assuming 24-hour values, which seems likely as you don't have an AM/PM marker):
to_date('May 1 2019 12:00', 'Mon DD YYYY HH24:MI', 'nls_date_language=English')
The format elements are in the documentation. I've included the optional third argument to to_date() because your month name has to be interpreted in English, regardless of your session settings.
it always removes the time part
Oracle dates always have both date and time parts, even if the time is set to midnight. You're probably seeing the result of that query as '01-MAY-19'.
Dates don't have any intrinsic human-readable format; Oracle uses its own internal representation, which you generally don't need to worry about.
In most clients and IDEs the session NLS_DATE_FORMAT setting is used to display native dates as strings. For historic reasons that still defaults to DD-MON-YY, despite Y2K, during database creation. it can be changed at database level, and sessions will then inherit that. But each session can override it, e.g. by issuing:
alter session set nls_date_format = 'YYYY-MM-DD HH24:MI:SS'
You can also explicitly convert a date value back to a string, and specify which format elements you want to include, via a to_char() call. Only do that when displaying a value - if you're storing dates or passing them around to functions, always do that as the proper date data type, not as strings. (If you have to pass them outside the database as strings, e.g. to a remote API, you'd usually want to use an ISO-8601 format).
db<>fiddle showing the default output, explicitly formatted as a string (again, for display only - do not store or manipulate dates as string), and with the session format modified.
In SQL Developer you can also go to Tools->Preferences->Database->NLS and change the 'Date format' there - that setting will then apply when you create new sessions, without having to issue alter session each time.
I know there are tons of post regarding iso8601 strings and timezones but I could not find anything that really pinpoints the problem I had recently.
I have an ISO 8601 RFC3339 formatted string like: 2021-03-31T12:00:00+03:00.
I want to display the time associated with this date in the local time of the provided date meaning I want exactly "12:00" as the output. If my formatter has dateFormat of HH:mm
If I use an ISO8601DateFormatter to extract the date everything seems to work fine and the associated Date object is 2021-03-31 09:00:00 +0000. Which makes sense since 12:00GMT+3 = 09:00GMT+0
However this completely removes Timezone information from the Date object (which I know is by design on iOS).
While I understand the design behind this (most of the time we eventually should display the time in the user device timezone). There are quite a few exceptions like travel applications where we almost alway want to display the local time of departure/arrival.
My solution was to store the json serialized dates as Strings and use a combination of ISO8601DateFormatter to create the Date object in UTC and a normal DateFormatter that reconstructs the TZ from the +03:00 substring.
What's the best approach to solve this ?
I added a time picker in my app but it returns the time in the format HH:MM.
I want the time picker to return the format HH:MM:SS so that the input is compatible with mySQL time format as well.
<ion-input type="time" [(ngModel)]="ChildData.Temperaturedatetime"></ion-input>
Component docs:
The datetime picker provides the simplicity of selecting an exact
format, and persists the datetime values as a string using the
standardized ISO 8601 datetime format. However, it's important to note
that ion-datetime does not attempt to solve all situtations when
validating and manipulating datetime values. If datetime values need
to be parsed from a certain format, or manipulated (such as adding 5
days to a date, subtracting 30 minutes, etc.), or even formatting data
to a specific locale, then we highly recommend using moment.js to
"Parse, validate, manipulate, and display dates in JavaScript".
Moment.js has quickly become our goto standard when dealing with
datetimes within JavaScript, but Ionic does not prepackage this
dependency since most apps will not require it, and its locale
configuration should be decided by the end-developer.
I send timestamps to my GWT client using GMT/Zulu time, with each string designated as such (ie. 2012-01-19T16:29:18Z, or 4:29pm GMT). How do I show this in the browser in the local timezone? So for me in CST I expect to see 10:29am.
If I do no formatting I get the date as 4:29pm, which I expect, If I use a TimeZone object of TimeZone.createTimeZone(0), I get for some reason 10:29PM (not AM as expected). I suppose I'm supposed to pass in something more meaningful than 0, but how do I obtain the right value for the where the browser is running?
J
You can get the time-zone offset that is configured in the browser using:
Date d = new Date();
d.getTimezoneOffset();
It won't give you the timezone name, I don't think that's possible to get.
Do you send the time as a timestamp, or string? I find the best approach is to send UTC timestamps to the client and then format them to whatever zone I need using DateTimeFormat/TimeZone. But I guess that if you are parsing the date string including the offset, you end up with a UTC timestamp anyway.
If you want the GWT client code to format the time in the browser time zone, you should pass the data from the server to the client as a java.util.Date object.
I'm using com.google.gwt.i18n.client.timezone to try and display a date (as at the server), but GWT automatically adds the current timezone to the date when formatting it, meaning The wrong date is shown in different timezones.
To combat this, I'm sending the server's timezone offset to the client and using that when formatting.
I live in Australia and the current timezone is +11 GMT/UTC, but the default timezone being displayed when I format the date is -11 GMT.
The offset from the server is +11 hours (as it should be), but when I try and format the date with this offset, I get the wrong date, and so I need to use the negative offset instead.
Why is the default timezone wrong?
When you are getting a date (particularly if you're parsing a date) make sure you specify the timezone. GWT's DateTimeFormat.parse only supports "RFC format" timezones, something like -0800 for Pacific time. If your server is sending dates in strings to the client, make sure it includes the timezone in this format.
Then when you convert the date to a string to present it to the user, make sure you use the overload of DateTimeFormat.format that specifies a TimeZone and pass the timezone that you want the date to be presented in (the timezone of the server, in your case.)
By default dates are presented in the timezone that the user's system is set to. Setting the default timezone in GWT (so you can ignore timezones and do everything in the server's timezone) is an open issue (3489) at the time I write this.