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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)));

Simple Date Parsing

I've been struggling a strange question.
I'm trying to parse a date format looks like this
"Thu, 18 Aug 2016 16:25:25 GMT"
to only Month and date like this
"08/18"
well I use two SimpleDateFormat, to parse and format the input and output
DateFormat inputFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z");
DateFormat outputFormat = new SimpleDateFormat("MM/dd");
however, everything seems to be correct when using genymotion emulator
but when it comes to the real phone, say sony Xperia Care
the following questions kept on comming
java.text.ParseException: Unparseable date: "Wed, 10 Aug 2016 15:40:57 GMT" (at offset 0)
so whats the reason that this happens?

Try to use
new SimpleDateFormat("EE MMM dd HH:mm:ss z yyyy",Locale.ENGLISH);

Your String-DAte has information that is related to an specific language, therefor you need to prepare the SimpleDAteFormat for such an information.
ERGO: you need to give a Locale
Example:
public static void main(String[] args) throws ParseException {
String dateStr = "Thu, 18 Aug 2016 16:25:25 GMT";
DateFormat inputFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z", Locale.ENGLISH);
Date d = null;
d = inputFormat.parse(dateStr);
DateFormat outputFormat = new SimpleDateFormat("MM/dd");
System.out.println("After format: " + outputFormat.format(d));
}

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);

SimpleDateFormat can parse date on android 4.0+ but fails on android 2.3 -

This is due to different jdk versions on android.
String string = "Tue Oct 16 00:00:55 IST 2012";
Date date = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy").parse(string);
and also tried
String string = "Tue Oct 16 00:00:55 IST 2012";
Date date = new SimpleDateFormat("EEE MMM dd HH:mm:ss 'UTC' yyyy").parse(string);
adding Locale in SimpleDateFormat constructor has no effect.
I have searched and got this but can't find any workaround.
Is there any workaround for this?

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"));