I have the two Date objects which I am trying to format from being in MM/DD/YYYY format to "yyyy-mm-dd HH:mm:ss" format.
The current approach I am using is to first format those dates using SimpleDateFormat which will return two Strings, then I have to convert this string back to Date to get the formatted final Date objects.
So I was wondering if there was a simpler way to change the Date object format without going in many steps?
Thanks
The format is irrelevant. Date simply represents the number of milliseconds since the Unix epoch.
Remember, Date has no concept of format, it doesn't care.
You should simply format the Date object with whatever formatters you need...
For example...
Date date = new Date();
System.out.println(date);
System.out.println(DateFormat.getDateTimeInstance().format(date));
System.out.println(new SimpleDateFormat("dd/MM/yyyy").format(date));
System.out.println(new SimpleDateFormat("yyyy MMMM EE").format(date));
System.out.println(new SimpleDateFormat("EEEE MMMM yyyy").format(date));
System.out.println(date);
Outputs...
Wed Jan 22 11:55:18 EST 2014
22/01/2014 11:55:18 AM
22/01/2014
2014 January Wed
Wednesday January 2014
Wed Jan 22 11:55:18 EST 2014
Note how the first and last values don't change. Date has no internal concept of format, that's the responsibility of the formatter.
For example, if I took the String value 22/01/2014 and parsed it back to a Date using SimpleDateFormat
Date date = new SimpleDateFormat("dd/MM/yyyy").parse("22/01/2014");
And then outputted the date value...
System.out.println(date);
It would output something like...
Wed Jan 22 00:00:00 EST 2014
The format has being lost. It would need to use an appropriate formatter to change what is displayed
Related
I am working with expiration date of card. I have a API where I will get expiration date in "yyMM" format as "String". Here I am trying to use
SimpleDateFormat with TimeZone.getTimeZone("UTC")
So my code is like
String a= "2011";
SimpleDateFormat formatter = new SimpleDateFormat("yyMM");
formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
Date date = formatter.parse(a);
System.out.println(date);
Now problem is, when I am passing 2011 the out it gives is Sat Oct 31 17:00:00 PDT 2020
Here you can see I am passing 11 as month but it is converting it to Oct instead of Nov.
Why?
And what other options I can use to convert string with yyMM to Date with Timezone?
You should use the Java 8 YearMonth class.
String a = "2011";
DateTimeFormatter inputFormat = DateTimeFormatter.ofPattern("yyMM");
YearMonth yearMonth = YearMonth.parse(a, inputFormat);
DateTimeFormatter outputFormat = DateTimeFormatter.ofPattern("MMMM yyyy");
System.out.println(yearMonth.format(outputFormat));
Output
November 2020
You parsed it fine, but it's printed in PDT, your local timezone.
Sat Oct 31 17:00:00 PDT 2020
Well, Date doesn't track timezones. The Calendar class does, which is internal to the formatter. But still, default print behavior is current timezone.
If you logically convert this output back to UTC, and it will be November 1 since PDT is UTC-7.
Basically, use java.time classes. See additional information here How can I get the current date and time in UTC or GMT in Java?
Server side code (server timezone is UTC):-
Date aDate = new Date();
java.sql.Timestamp aTimestamp = new java.sql.Timestamp(aDate.getTime());
Client side (Mobile app, timezone GMT +5:30):-
Hitting a service request which runs above code on server side
The issue is when i debugged on server, found following values :-
aDate.getTime() prints to -> 1470472883877 milliseconds i.e., Sat Aug 06 2016 14:11:23 GMT+0530
but
aTimestamp prints to -> (java.sql.Timestamp) 2016-08-06 08:41:44.109
It's kinda weird, i've no idea what's going on in conversion !! please help
UTC and GMT are formats.
java.util.Date and java.sql.Timestamp are independent of the timezone. They store a long time in ms for representing their inner state.
For information, Calendar is timezone aware.
So with Date or Timestamp, to differentiate GMT or UTC format in an output, you have to use a formater which outputs the date into string by being aware the timezone.
In your output : 2016-08-06 08:41:44.109, you don't use a formater which is aware of the timezone. It's probably the result of a toString() on the java.sql.Timestamp instance or something of similar.
What you consider as a conversion is not a conversion but a formatting since the timestamp stays the same between the two objects.
If you want to display in the UTC format, use the appropriate formater with a
SimpleDateFormat for example :
SimpleDateFormat dt= new SimpleDateFormat("MM/dd/yyyy hh:mm:ss z");
dt.setTimeZone(TimeZone.getTimeZone("UTC"));
String dateStringInUTC = dt.format(new Date(yourSqlTimestamp.getTime()));
The following is probably what you are looking for:
Calendar cal = Calendar.getInstance(Locale.GERMANY); // use your locale here
Timestamp aTimestamp = new Timestamp(cal.getTimeInMillis());
System.out.println(aTimestamp);
System.out.println(cal.getTime());
And the output:
2016-08-06 19:12:54.613
Sat Aug 06 19:12:54 CEST 2016
I have a date with value "Sat Nov 14 00:00:00 GMT+05:30 2015".I need to convert this variable to a string date with format "yyyy-MM-dd hh:mm:ss".For that i used the below code,
SimpleDateFormat dtf=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
String date=dtf.format(reDate);
where reDate has the value "Sat Nov 14 00:00:00 GMT+05:30 2015".But after conversion i got the value as "2015-11-14 12:00:00".The time "00:00:00" get changed to "12:00:00".How that happens? I need to get the exact time after conversion.That is the result as "2015-11-14 00:00:00".How to do that? Please help me to solve this.
You should be using HH instead of hh as mentioned here like:
SimpleDateFormat dtf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String date=dtf.format(reDate);
I have followed this SO answer for datetime conversion of 8601.
I will cite an example straight from w3 :
1994-11-05T08:15:30-05:00 corresponds to November 5, 1994, 8:15:30 am, US Eastern Standard Time.
1994-11-05T13:15:30Z corresponds to the same instant.
And this is what I run in android
SimpleDateFormat sdfSource = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZZ");
dateTime = sdfSource.parse("2014-03-06T11:30:00-05:00");
System.out.println(dateTime); //Thu Mar 06 18:30:00 EET 2014
Obviously .parse()'s output is the local aware datetime. There has been a conversion from EST(-05:00) to EET (+02:00) since now I am in this timezone. However I do not want this auto-convertion.
Is there a way to parse a datetime string inyyyy-MM-dd'T'HH:mm:ssZZZZZ format and display THAT timezone's datetime? Preferable output:
Thu Mar 06 11:30:00 EST 2014
The EST and my location is an example. It can be any other timezones as well.
Internally Date objects are in UTC and that's what they're parsed to.
You cannot retrieve the original timezone from the Date but you can attempt to retrieve it from the original ISO-8601 stamp, and use it when formatting.
When you convert it to a string with toString(), it uses your local settings to format the date. If you want a specific representation, use a formatter to format the output, e.g.
int rawTimeZoneOffsetMillis = ...; // retrieve from ISO-8601 stamp and convert to milliseconds
TimeZone tz = new SimpleTimeZone(rawTimeZoneOffsetMillis, "name");
DateFormat outputFormat = DateFormat.getDateTimeInstance();
outputFormat.setTimeZone(tz);
System.out.println(df.format(dateTime));
ISO-8601 timestamps are not completely parseable with SimpleDateFormat. This answer has some code to work around some of the limitations.
Use sdfSource.setTimeZone() method
SimpleDateFormat sdfSource = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZZ");
sdfSource.setTimeZone(TimeZone.getTimeZone("EST")); //give the timezone you want
dateTime = sdfSource.parse("2014-03-06T11:30:00-05:00");
System.out.println(dateTime); //Thu Mar 06 18:30:00 EET 2014
This should do fine.
Although you should not be worried while parsing the date as it is parsed to correct value can be displayed in any format or timezone you want.
SimpleDateFormat sdfSource = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZZ");
sdfSource.setTimeZone( TimeZone.getTimeZone( "EST" ) );
dateTime = sdfSource.parse("2014-03-06T11:30:00-05:00");
System.out.println(sdfSource.format(dateTime)); //Thu Mar 06 18:30:00 EET 2014
I am getting different date formats below dd-MM-yyyy,dd/MM/yyyy,yyyy-MM-dd,yyyy/MM/dd
SimpleDateFormat sm1 = new SimpleDateFormat("dd-MM-yyyy");
String date = "01-12-2013";
System.out.println("Date 1 is "+sm1.parse(date));
date = "2013-12-01";
System.out.println("Date 1 is "+sm1.parse(date));
the same simple date format gives the below result eventhough date format is wrong(ie:-2013-12-01).Below the results.
Date 1 is Sun Dec 01 00:00:00 IST 2013
Date 1 is Sun Jun 05 00:00:00 IST 7
You need to setLenient(false) to make parse() method throw ParseException for unparsable case
I have tried Jigar Joshi's answer.
==========================code=======================================
SimpleDateFormat sm1 = new SimpleDateFormat("dd-MM-yyyy");
sm1.setLenient(false);
String date = "01-12-2013";
System.out.println("Date 1 is "+sm1.parse(date));
date = "2013-12-01";
System.out.println("Date 1 is "+sm1.parse(date));
=========================Result========================================
Date 1 is Sun Dec 01 00:00:00 CST 2013
Exception in thread "main" java.text.ParseException: Unparseable date: "2013-12-01"
at java.text.DateFormat.parse(DateFormat.java:337)
at workflow.Test.main(Test.java:14)
Your date format is dd-MM-yyyy. That means the parser is expecting some day, month, and year format.
From the SimpleDateFormat documentation: the number of pattern letters in a Number type formatter is the minimum. So, while 2013 wouldn't make sense in our mind, it fits within the formatter's bounds.
You have provided 2013-12-01 as to fit into that format. What it appears the formatter is doing is providing December 1 (insert timezone here), and then adding 2,013 days to it.
That turns out to be June 6, 7 AD. There's some wiggle room for your timezone (I'm not sure which of the five timezones IST represents is actually yours).
So, believe it or not...the formatter is correct. Be very careful as to what kind of format you specify or allow in your dates!
If you don't want that parsed, then specify setLenient(false) on your instance of sm1.