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Trouble formatting date in Java [duplicate]

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DateTimeParse Exception
(2 answers)
Closed 2 years ago.
I've tried several methods with Java Joda Time, Date Time with locale and commons-lang and can't get this date formatted.
Input
Mon Dec 28 15:18:16 UTC 2020
Output
Desired output format yyyy-MM-dd HH:mm:ss.SSS
When I use a format pattern like EEE MMM dd HH:mm:ss Z YYYY the date is off my a couple days and the timezone seems completely wrong.
Formatter:
private static final DateTimeFormatter DATE_TIME_FORMATTER =
DateTimeFormatter
.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")
.withLocale(Locale.US)
.withZone(ZoneId.systemDefault());
DateUtils.parseDate (Optional
.ofNullable(record)
.map(CustomerModel::getCustomerAudit)
.map(customerAudit::getCreated)
.map(auditItem::getDate).get ().toString (), "EEE MMM dd HH:mm:ss YYYY")

When debugging parsing issues, if possible, reverse the operation and generate the text you're supposed to be parsing, to verify the parsing rules, i.e. the date format string. This applies to date parsing, JAXB parsing, and any other (de)serializing operation that is bi-directional. It makes finding conversion rule issues a lot easier.
So, let us check the format string in the question, with the shown date value:
ZonedDateTime dateTime = ZonedDateTime.of(2020, 12, 28, 15, 18, 16, 0, ZoneOffset.UTC);
DateTimeFormatter fmt = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss Z YYYY", Locale.US);
System.out.println(dateTime.format(fmt));
Output
Mon Dec 28 15:18:16 +0000 2021
Oops! That doesn't fit the expected output, aka the input we desire to parse:
Mon Dec 28 15:18:16 UTC 2020
So what went wrong?
The year is wrong because it's supposed to be uuuu (year), not YYYY (week-based-year).
The time zone is wrong because Z does support a text representation. Use VV or z instead.
DateTimeFormatter fmt = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss z uuuu", Locale.US);
ZonedDateTime dateTime = ZonedDateTime.parse("Mon Dec 28 15:18:16 UTC 2020", fmt);
System.out.println(dateTime);
System.out.println(dateTime.format(DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss.SSS")));
Output
2020-12-28T15:18:16Z[UTC]
2020-12-28 15:18:16.000
As you can see, it now parsed correctly.

The code in the question makes little sense:
It is formatting a Date value to text using toString(), just to attempt parsing that back.
It is using Optional for simple null-handling (which is discouraged), but then unconditionally calling get(), which means a null value will throw exception anyway.
The code should be:
record.getCustomerAudit().getCreated().getDate().toInstant()
This of course makes the entire question moot.

Works fine for me.
String s = "Mon Dec 28 15:18:16 UTC 2020";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss VV yyyy",
Locale.ENGLISH);
ZonedDateTime zdt = ZonedDateTime.parse(s, formatter);
formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS", Locale.ENGLISH);
System.out.println(zdt.format(formatter));
Output is
2020-12-28 15:18:16.000
Am I missing something?

Have you tried with SimpleDateFormat?
String dateString = "Mon Dec 28 15:18:16 UTC 2020";
SimpleDateFormat input = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy", Locale.ENGLISH);
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS", Locale.ENGLISH);
System.out.println(output.format(input.parse(dateString)));
With timezone:
String dateString = "Mon Dec 28 15:18:16 UTC 2020";
SimpleDateFormat input = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd z HH:mm:ss.SSS");
input.setTimeZone(TimeZone.getTimeZone("UTC"));
output.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(output.format(input.parse(dateString)));

Unparseable date error

I have this
java.text.ParseException: Unparseable date: "Thu, 21 Apr 2016 18:00:00
+0000" (at offset 26)
when using new SimpleDateFormat("E, dd MMMM yyyy hh:mm:ss a", Locale.ROOT);
Why is that can be?
EDIT:
This is correct answer due to parsing pattern.
SimpleDateFormat f = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z", Locale.ROOT);
And also Android somehow gives error when the Locale is ROOT and when it is ENGLISH everything works fine.

You are using the wrong format. You should be using EEE, dd MMM yyyy HH:mm:ss Z instead of E, dd MMMM yyyy hh:mm:ss a.
Here is the code snippet:
public static void main (String[] args) throws Exception
{
String foo = "Thu, 21 Apr 2016 18:00:00 +0000";
SimpleDateFormat f = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z", Locale.ROOT);
System.out.println(f.parse(foo));
}
Output:
Thu Apr 21 18:00:00 GMT 2016

Use EEE, dd MMM yyyy HH:mm:ss Z

String to Date parse java

I want to parse a string Thu Apr 03 07:53:53 BST 2014 to a Date object in java. I don't know how to handle the 'BST' part - i have tried this
date = new SimpleDateFormat("E MMM dd HH:mm:ss yyyy", Locale.ENGLISH).parse(string);
but getting Unparseable date: "Thu Apr 03 07:53:53 BST 2014"

You're missing the BST part. Use zzz for it:
date = new SimpleDateFormat("E MMM dd HH:mm:ss zzz yyyy", Locale.ENGLISH).parse(string);

That is because the date does not match the format string. The date has a timezone but the format string does not.
Thu Apr 03 07:53:53 BST 2014
E MMM dd HH:mm:ss ??? yyyy
Adding timezone (z) to the format string solves your problem:
date = new SimpleDateFormat("E MMM dd HH:mm:ss z yyyy", Locale.ENGLISH)
.parse(string);

You could use the Joda Time library.

Try this one along with your locale using SimpleDateFormat.
// Thu Apr 03 07:53:53 BST 2014
SimpleDateFormat format = new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy", Locale.ENGLISH);
Date date = format.parse("Thu Apr 03 07:53:53 BST 2014");
Description of each pattern
EEE - Day name in week (in 3 chars)
MMM - Month in year (in 3 chars)
dd - Day in month (in 2 digits)
kk - Hour in day (1-24) (in 2 digits)
mm - Minute in hour (in 2 digits)
ss - Second in minute (in 2 digits)
z - Time zone (General time zone)
yyyy - Year (in 4 digits)

date = new SimpleDateFormat("E MMM dd HH:mm:ss z yyyy", Locale.ENGLISH)
.parse(string)
Your time format doesn't match with the string. You missed the z in your format where it refers to the timezone. Check out this link for more detailsSimpleDateFormat

Android can't parse string to date

I have this string
Wed, 08 Jan 2014 9:30 am WET
and needed to be parsed to a Date object, I tried lot of masks but didn't work, here is the last thing I tried that I thought it would work with but didn't
SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy hh:mm aaa z", Locale.ENGLISH);
thanks
stack trace
01-08 14:25:25.906: W/System.err(13288): java.text.ParseException: Unparseable date: "Wed, 08 Jan 2014 11:59 am WET"
01-08 14:25:25.914: W/System.err(13288): at java.text.DateFormat.parse(DateFormat.java:626)
I ended up using this instead
SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy hh:mm aaa", Locale.ENGLISH);
Date date = dateFormat.parse(dateString.substring(0, dateString.length() - 4));
that WET part was the cause so I removed it, it wouldn't give the exact time but I only need the day and month,

Give a Locale to your Formatter where days and months are in English, otherwise it will use your default locale (that I presume is not English) and hence can't parse your String.
SimpleDateFormat dateFormat =
new SimpleDateFormat("EEE, dd MMM yyyy hh:mm aaa z", Locale.ENGLISH);

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"));