I have a Grails application that needs to parse Dates out of strings that were created with the date.toString() method.
My system's default date.toString() format is "Thu Apr 20 00:27:00 CEST 2006" so I know I can turn a Date into a string and then back into an object using Date.parse('EEE MMM dd HH:mm:ss z yyyy', new Date().toString()).
But that's lame! I shouldn't have to reverse engineer the system's default date format. Plus, I'm not sure under what circumstances the default date format can change, thus breaking that code.
Is there a way to parse a date.toString() back into a Date without using a hand-rolled formatter like that?
Thanks!
Update: I filed this Jira ticket to get such a feature added Groovy. Someone commented on the ticket that Java's date.toString() method is hard-coded to use EEE MMM dd HH:mm:ss z yyyy. That sucks for Java to be so inflexible, but it makes it easier for me to live with hard-coding the formatter!
There's a page over here showing how bad this is in Java (and hence in Groovy)
I agree that there should be a Date.parse method in Groovy which uses this default Date.toString() format.
Maybe it's worth adding a request for improvement over on the Groovy JIRA?
As a temporary workaround, you could add your parse method to the String metaClass in Bootstrap.groovy?
String.metaClass.parseToStringDate = { Date.parse( 'EEE MMM dd HH:mm:ss z yyyy', delegate ) }
Then you can do:
new Date().toString().parseToStringDate()
anywhere in the groovy portions of your grails app
I haven't worked with Grails and I know this is not the answer to your question, but as a workaround, couldn't you just save the format-string as a global variable?
if u use it to convert to json, maybe code below could help:
//bootstrap
JSON.registerObjectMarshaller(Date) {
return it?.format("yyyy-MM-dd HH:mm:ss")
}
Related
in Java I set the date as time in mSec since 1970, e.g. futuredate=1640995200000l //1 Jan 2022.
When this is compiled into JavaScript by GWT, I believe it uses the Jsdate library which says it is a native javascript date object
1 jan 2022 ends up as this object in the JavaScript _.futuredate={l:3120128, m:391243, h:0}
Can someone help me interpret this format please, it doesn't quite make sense to me
thanks
To work with date and time on the GWT client side one can use com.google.gwt.i18n.shared.DateTimeFormat. com.google.gwt.i18n.shared.DateTimeFormat.PredefinedFormat includes already many predefined formats, but you can naturally use your own, such as "EEEE, y MMMM dd".
Based on your example:
Date myDate = DateTimeFormat.getFormat("dd.MM.yyyy").parse("01.01.2022");
DateTimeFormat myFormat = DateTimeFormat.getFormat(PredefinedFormat.ISO_8601);
String s = myFormat.format(myDate);
The first line only simulates the date that you already set in Java and it is meant to show another example of a date format and how to parse a String.
I am retrieving a date from a database in the following format:
vardate = '01/20/2017 09:20:35' - mm/dd/yyyy hh:mm:ss
I want to convert it to the format dd-mm-yyyy hh:mm:ss
Can I get some guidance on how I could get the format I want?
Date formatting in Lua is pretty simplistic. If you only need to convert it from one format to another, and that format does not change, you could simply use string.match:
function convertDate(vardate)
local d,m,y,h,i,s = string.match(vardate, '(%d+)/(%d+)/(%d+) (%d+):(%d+):(%d+)')
return string.format('%s/%s/%s %s:%s:%s', y,m,d,h,i,s)
end
-- Call it this way
convertDate('01/20/2017 09:20:35')
If you need something more involved, I suggest using an external library.
function ConvertDate(date)
return (date:gsub('(%d+)/(%d+)/(%d+) (%d+:%d+:%d+)','%2-%1-%3 %4'))
end
-- test
print(ConvertDate('01/20/2017 09:20:35'))
I'm currently working with embarcadero c++, this is the first time I'm working with it so it's completely new to me.
What I'm trying to achieve is to get the current date, make sure the date has the "dd/MM/yyyy" format. When I'm sure this is the case I want to add a month to the current date.
So let's say the current date is 08/18/2016 this has to be changed to 18/08/2016 and then the end result should be 18/09/2016.
I've found that there is a method for this in embarcardero however I'm not sure how to use this.
currently I've only been able to get the current date like this.
TDateTime currentDate = Date();
I hope someone will be able to help me out here.
I figured it out.
After I've searched some more I found the way to use the IncMonth method on this page.
The example given my problem is as follows:
void __fastcall TForm1::edtMonthsExit(TObject *Sender)
{
TDateTime StartDate = edtStartDate->Text;
int Months = edtMonths->Text.ToInt();
TDateTime NextPeriod = IncMonth(StartDate, Months);
edtNextPeriod->Text = NextPeriod;
}
After looking at I changed my code accordingly to this
TDateTime CurrentDate = Date();
TDateTime EndDate = IncMonth(CurrentDate, 1);
A date object doesn't have a format like "dd/MM/yyyy". A date object is internally simply represented as a number (or possibly some other form of representation that really isn't your problem or responsibility).
So you don't have to check if it's in this format because no date objects will ever be in this format, they simply don't have a format.
You will have to do additions/subtractions on the Date object that the language or library gives you, THEN (optionally) you can format it to a human-readable string so it looks like 18/08/2016 or 18th of August 2016 or whatever other readable format that you choose.
It might be that the TRANSFER of a date between 2 systems is in a similar format, but then formatting the date like that is entirely up to you.
As for how to do that, the link you posted seems like a possible way (or alternatively http://docwiki.embarcadero.com/Libraries/Berlin/en/System.SysUtils.IncMonth), I'm afraid I can't give you an example as I'm not familiar with the tool/language involved, I'm just speaking generically about Date manipulations and they should ALWAYS be on the raw object.
I'm trying to convert a string of text into a date with the following code:
//Input String
str = "14/01/26,12:13:13+00"
//Format
format = new java.text.SimpleDateFormat("yy/MM/dd,HH:mm:ssz")
//Conversion
format.parse(str)
But I obtain the following:
Exception: Unparseable date: "14/01/26,12:13:13+00"
How does my format have to be changed in order to parse this date correctly?
+00 is invalid time zone. It should be +0000.
You could add 00 to str and replace z with Z in pattern to use RFC 822 time zone format:
new java.text.SimpleDateFormat("yy/MM/dd,HH:mm:ssZ").parse(str + "00")
// java.util.Date = Sun Jan 26 16:13:13 MSK 2014
java.util.Date (and java.text.SimpleDateFormat) is not the best choice for project. See this answer for some details.
As a bonus DateTimeFormat from Joda-Time allows you to parse your str without modifications:
// I'm using the same pattern with `Z` here
DateTimeFormat.forPattern("yy/MM/dd,HH:mm:ssZ").parseDateTime(str)
// org.joda.time.DateTime = 2014-01-26T16:13:13.000+04:00
If you're looking for "correctness", then don't use SimpleDateFormat!
For one thing, it's not thread safe... and it's silently unsafe, you'll just end up with corrupt dates and no error being thrown. As you're using Scala then it's a fair bet that concurrent programming and thread safety will apply to you.
Use JodaTime, perhaps with one of the Scala wrappers. It gives you some far nicer tools for building date parsers, and generally does the right thing if you simply use the default parser without specifying any format string.
I am in the unfortunate position that I need to use a composite id in a Grails app where I work with legacy data. This means I have to override some actions in the controller, but as I did this I was struck by the fact that I could not use use a date argument directly as a parameter to a dynamic method.
Instead of just doing MyLegacyObj.findBySystemIdAndLogDate(params.systemId, params.logDate), I first needed to parse the date string before giving it to the dynamic method. To further complicate matters I had no idea what format the date string had (until I added lots of log.debug() string to the output). So now I have a bit of code looking like this
def formatter = new SimpleDateFormat("EEE MMM d HH:mm:ss z yyyy")
MyLegacyObj.findBySystemIdAndLogDate(params.systemId, formatter.parse(params.logDate));
This feels unoptimal, no to say dangerous (what if the date format changes with the locale?)? What would be a recommended way of doing this, and do I really need to parse dates at all?
Date is a pretty complex object and params are just Strings, so Date is submitted in parts. It is "magically" assembled from the parts when assigning x.properties = params.
Command object will do the work for you, if you add a Date field to it.
It has nothing to do with methods' dynamic or static invocation. Your GSP that renders Date editor might interfere too.