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DateTime format needed chnages as expected [duplicate]

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Java date format - including additional characters
(5 answers)
Closed 2 years ago.
I want to display time as "02 Sep 2020 at 12:24 AM" (mind the at between date and time).
The current format I am using is "dd MMM yyyy hh:mm aaa",
which displays time as "28 Aug 2020 11:32 AM".
How can I put an at before the time?

You can add string literals to a date format by surrounding them with single quotes ('):
SimpleDateFormat sdf = new SimpleDateFormat("dd MMM yyyy 'at' hh:mm aaa");
// Here -------------------------------------------------^--^
String formatted = sdf.format(myDateVariable);

If you use java.time for this, you can define a java.time.format.DateTimeFormatter to parse a String, use it to parse the String to a java.time.LocalDateTime and define & use another DateTimeFormatter that includes the at escaping it in the pattern by enclosing it in single-quotes:
public static void main(String[] args) {
String dateTime = "02 Sep 2020 12:24 AM";
DateTimeFormatter parserDtf = DateTimeFormatter.ofPattern("dd MMM uuuu hh:mm a",
Locale.ENGLISH);
DateTimeFormatter outputDtf = DateTimeFormatter.ofPattern("dd MMM uuuu 'at' hh:mm a",
Locale.ENGLISH);
LocalDateTime ldt = LocalDateTime.parse(dateTime, parserDtf);
System.out.println(ldt.format(outputDtf));
}
This code produces the output
02 Sep 2020 at 12:24 AM

Just wrap the word in single quotes.
"dd MMM yyyy 'at' hh:mm aaa"

SimpleDateFormat formatter = new SimpleDateFormat("dd MMM yyyy 'at' HH:mm:ss z");
Date date = new Date(System.currentTimeMillis());
System.out.println(formatter.format(date));

In JAVA, how do you calculate time difference between two dates in string format where both the times are in different time formats and time zones?

I have two strings containing Dates in different formats.
For example :
String Date1 = "Fri, 25 Jan 2019 11:34:11 GMT";
String Date2 = "Thu, 24 Jan 2019 17:14:21 EST";
In JAVA, how do I calculate the time difference between them given that both of them have different timezone (like GMT and EST) above?
Also, note that Date1 and Date2 can be in any of the below-given formats :
private static final String[] formats = {
"EEE, d MMM yyyy HH:mm:ss Z", "EEEE, MMMM d, yyyy, HH:mm Z",
"EEE, d MMM yyyy HH:mm:ss z",
"yyyy-MM-dd'T'HH:mm:ss'Z'", "yyyy-MM-dd'T'HH:mm:ssZ",
"yyyy-MM-dd'T'HH:mm:ss", "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
"yyyy-MM-dd'T'HH:mm:ss.SSSZ", "yyyy-MM-dd HH:mm:ss",
"MM/dd/yyyy HH:mm:ss", "MM/dd/yyyy'T'HH:mm:ss.SSS'Z'",
"MM/dd/yyyy'T'HH:mm:ss.SSSZ", "MM/dd/yyyy'T'HH:mm:ss.SSS",
"MM/dd/yyyy'T'HH:mm:ssZ", "MM/dd/yyyy'T'HH:mm:ss",
"yyyy:MM:dd HH:mm:ss", "yyyyMMdd", };

Joda DateTimeFormatter Invalid format

I am getting the above error, but to me everything seems to be correct.
What I am doing wrong?
DateTimeFormatter simpleDateFormatInput= DateTimeFormat.forPattern("EEE, dd MMM yyyy HH:mm:ss Z");
DateTime datetime = simpleDateFormatInput.parseDateTime(pubDate);
Where pubDate is Sat, 30 Jan 2016 12:23:53 +0100

The day and/or month from your input String may not match those from your default Locale. Try
DateTimeFormatter simpleDateFormatInput =
DateTimeFormat.forPattern("EEE, dd MMM yyyy HH:mm:ss Z").withLocale(Locale.US);

Parse date in android

I have the following code to pase a date
DateFormat df = new SimpleDateFormat("EEE, dd MMM yyyy kk:mm:ss", Locale.getDefault());
Date _pubDate = df.parse(_pubDateE.getFirstChild().getNodeValue());
But I get this error:
java.text.ParseException: Unparseable date: "Fri, 12 Aug 2011 15:34:47 CEST"
What is wrong ?

You're missing the timezone in the date format at the end, in your exception message, the "CEST" part.
Your code
DateFormat df = new SimpleDateFormat("EEE, dd MMM yyyy kk:mm:ss", Locale.getDefault());
should be
DateFormat df = new SimpleDateFormat("EEE, dd MMM yyyy kk:mm:ss z", Locale.getDefault());
You might want to read SimpleDateFormat
Edit
At the bottom of this page, the timezone format is more cleary explained
Clearer Timezone format

I think you need to add zzz in the end (for timezone):
"EEE, dd MMM yyyy kk:mm:ss zzz"

The date string is not in the format you specified. Notice the time zone at the end?

You probably want: new SimpleDateFormat("EEE, dd MMM yyyy kk:mm:ss zzz", Locale.getDefault());

Parse RSS pubDate to Date object in java

How can I parse a pubDate from a RSS feed to a Date object in java.
The format in the RSS feed:
Sat, 24 Apr 2010 14:01:00 GMT
What I have at the moment:
DateFormat dateFormat = DateFormat.getInstance();
Date pubDate = dateFormat.parse(item.getPubDate().getText());
But this code throws an ParseException with the message Unparseable date

You can define the date format you are trying to parse, using the class SimpleDateFormat:
DateFormat formatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz");
Date date = formatter.parse("Sat, 24 Apr 2010 14:01:00 GMT");
Additionally, for non-English Locale's, be sure to use the following when parsing dates in English:
new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.ENGLISH);

If you need to have an RFC822 compliant date, try this :
DateFormat dateFormatterRssPubDate = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z", Locale.ENGLISH);

For the lucky one that can use the Java 8 LocalDateTime:
LocalDateTime localDateTime = LocalDateTime.from(DateTimeFormatter.RFC_1123_DATE_TIME.parse("Sat, 24 Apr 2010 14:01:00 GMT"));