The default format for Date.toString() seems to be, in an US locale, something like:
Thu Nov 24 15:20:52 CET 2016
Oracle database has a function "TO_DATE" that allows convert from string to date. First argument is the date format.
Which is the correct date format to map a Java Date.toString() string? Is it:
DAY MONTH DD HH24:MI:SS TZD YYYY
?
Thanks.
An Oracle DATE data type does not have a time zone - you need a TIMESTAMP WITH TIMEZONE data type:
SELECT TO_TIMESTAMP_TZ(
'Thu Nov 24 15:20:52 CET 2016',
'DY MON DD HH24:MI:SS TZR YYYY'
)
FROM DUAL
If you want to convert to a DATE (and the time zone region is always CET) then you can use:
SELECT TO_DATE(
'Thu Nov 24 15:20:52 CET 2016',
'DY MON DD HH24:MI:SS "CET" YYYY'
)
FROM DUAL
If you want it as a DATE data type and to respect the time zone in the original string then you will need to (1) convert it to a TIMESTAMP WITH TIMEZONE data type; (2) convert that value to a standardized time zone (UTC is often used for this); then (3) convert that to a date:
SELECT CAST(
TO_TIMESTAMP_TZ(
'Thu Nov 24 15:20:52 CET 2016',
'DY MON DD HH24:MI:SS TZR YYYY'
)
AT TIME ZONE 'UTC'
AS DATE
)
FROM DUAL;
Which will output the date 2016-11-24 14:20:52 (the UTC representation of the input date).
In Java, default Date format with toString() method is EEE MMM dd HH:mm:ss zzz yyyy. I don't know why but Oracle doesn't supports parse syntax 'EEE','MMM' and 'zzz' .
Read more : Table 9-4 Datetime Format Elements
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?
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 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
I am a little confused with the unix time stamp conversion to java.util.Date involving the time zones.
I have a unix time stamp that is "1367832568". it is a UTC date (Mon May 06 17:29:28 GMT+00:00 2013). when i do following :
Date d = new Date(1367832568 * 1000);
it gives me Mon May 06 17:29:28 GMT+08:00 2013 which is not correct. it should give me:
Mon May 07 01:29:28 GMT+08:00 2013
because the unix time stamp is actually a UTC date. so this is confusing. what should i do to convert the UTC unix time stamp to correctly convert to a UTC Date object.
I'm not sure exactely how are you formatting your date object, but by setting the timezone to the dateformat object (to GMT) I'm able to get
Mon May 06 09:29:28 GMT 2013 AM
which is the same date you are looking for.
long time = 1367832568 * (long) 1000;
Date date = new Date(time);
SimpleDateFormat format = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy a");
format.setTimeZone(TimeZone.getTimeZone("GMT"));
Log.d("date", format.format(date));
How to convert the date Tue Nov 13 14:35:04 +0000 2012 String format to date in Java?
I know of Date.parse(String) but I don't know which format I should use for the date. Do I have to modify the string so that it can be parsed into date, and if yes then how?
Use SimpleDateFormat, with a format string of
"E MMM dd HH:mm:ss Z yyyy"
You should explicitly use Locale.US assuming these will definitely use English month/day names. (You don't want to be trying to parse French names just because the default locale is French, for example.)
Also, don't forget that the Date value returned will have no knowledge of the original time zone - it will have the right value for the instant represented in the original text, but don't expect the result of calling toString() to use the same zone - Date.toString() always uses the default time zone.
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss Z yyyy", Locale.US);
Date test = sdf.parse("Tue Nov 13 14:35:04 +0000 2012");
System.out.print(test.toString());