How do I convert an Arabic String date to a java 8 date object?

Question

I'm working on a web monitoring project in Arabic and I want to convert string date like this one:

الاثنين 24 أبريل 2017 - 15:00

to Java 8 date object. How can I do that?

Answer 1

The answers of @Ole and @slim are working, but not for the reason they think.

First observation - the nu-extension is unnecessary for given example:

Oles suggestion would also work for the locale new Locale("ar", "SA") instead of Locale.forLanguageTag("ar-SA-u-nu-arab"). So what does the unicode-nu-extension here? Nothing. Next question:

What is the nu-extension supposed to do here?

The nu-code-word "arab" is specified by the unicode consortium to yield arabic-indic digits. But the input to be parsed does only have western digits 0-9 (which are historically overtaken from Arab people and specified as code word "latn" - a misnomer by the way). So if the nu-extension had really done its job here then parsing should have failed because arabic-indic digits are not 0-9 but:

٠ ١ ٢ ٣ ٤ ٥ ٦ ٧ ٨ ٩

Obviously, the nu-extension is not supported in general by new time-API in Java-8.

Does SimpleDateFormat support the nu-extension?

Using debugging of following code, I discovered that the nu-extension is only supported for Thai-numerals (see also official javadoc of class java.util.Locale but not for arabic-indic digits:

SimpleDateFormat sdf = 
    new SimpleDateFormat("EEEE d MMMM yyyy - HH:mm", Locale.forLanguageTag("ar-SA-nu-arab"));
Date d = sdf.parse(dateTimeString);
System.out.println(d);
String formatted = sdf.format(d);
System.out.println(formatted);
System.out.println(sdf.format(d).equals(dateTimeString));

sdf = new SimpleDateFormat("EEEE d MMMM uuuu - HH:mm", Locale.forLanguageTag("ar-SA-u-nu-thai"));
String thai = sdf.format(d);
System.out.println("u-nu-thai: " + thai);

I assume the class DateTimeFormatter of Java-8 also supports Thai numerals.

Conclusion:

Forget the nu-extension. Just construct the locale via the old-fashioned way without unicode extension and adapt Oles answer this way. It works because your input only has western digits 0-9.

For extensive i18n-support including the nu-extension for various numbering systems (if you have such input), you might consider external libraries (for example ICU4J or my lib Time4J).

Answer 2

Edit: with thanks to slim and Meno Hochschild for inspiration:

String dateTimeString = "الاثنين 24 أبريل 2017 - 15:00";

DateTimeFormatter formatter
        = DateTimeFormatter.ofPattern("EEEE d MMMM uuuu - HH:mm", new Locale("ar"));
LocalDateTime dateTime = LocalDateTime.parse(dateTimeString, formatter);
System.out.println(dateTime);

This prints:

2017-04-24T15:00

Answer 3

I don't know enough Arabic to understand an Arabic formatted date. However this code:

Locale arabicLocale = new Locale.Builder().setLanguageTag("ar-SA-u-nu-arab").build();

LocalDate date = LocalDate.now();
DateTimeFormatter formatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).withLocale(arabicLocale);

String formatted = date.format(formatter);
System.out.println(formatted);
System.out.println(formatter.parse(formatted));

Yields this output:

26 أبريل, 2017
{},ISO resolved to 2017-04-26

The code to create the Locale is from an answer to Setting Arabic numbering system locale doesn't show Arabic numbers

You can fine-tune this format by defining your own FormatStyle.