Java – How to format a date in uppercase

calendardateformattingjava

I'm trying to format a date in this way:

Monday 4, November, 2013

This is my code:

private static String formatDate(Date date) {
  Calendar calenDate = Calendar.getInstance();
  calenDate.setTime(date);
  Calendar today = Calendar.getInstance();
  if (calenDate.get(Calendar.DAY_OF_MONTH) == today.get(Calendar.DAY_OF_MONTH)) {
    return "Today";
  }
  today.roll(Calendar.DAY_OF_MONTH, -1);
  if (calenDate.get(Calendar.DAY_OF_MONTH) == today.get(Calendar.DAY_OF_MONTH)) {
    return "Yesterday";
  }
  // Guess what buddy
  SimpleDateFormat sdf = new SimpleDateFormat("EEEEE d, MMMMM, yyyy");
  // This prints "monday 4, november, 2013" ALL in lowercase
  return sdf.format(date);
}

But I don't want to use some split method or do something like that. Isn't there some pattern that I can include in the regexp to make it be uppercase at the begin of each word?

UPDATE
I'm from a hispanic country, something like new Locale("es", "ES") I get "martes 7, noviembre, 2013" when what I need is "Martes 7, Noviembre, 2013".

Best Answer

You can change the strings that SimpleDateFormat outputs by setting the DateFormatSymbols it uses. The official tutorial includes an example of this: http://docs.oracle.com/javase/tutorial/i18n/format/dateFormatSymbols.html

Reproduction of the example from the tutorial, applied to the "short weekdays":

String[] capitalDays = {
    "", "SUN", "MON",
    "TUE", "WED", "THU",
    "FRI", "SAT"
};
symbols = new DateFormatSymbols( new Locale("en", "US"));
symbols.setShortWeekdays(capitalDays);

formatter = new SimpleDateFormat("E", symbols);
result = formatter.format(new Date());
System.out.println("Today's day of the week: " + result);

Intl.NumberFormat

JavaScript has a number formatter (part of the Internationalization API).

// Create our number formatter.
var formatter = new Intl.NumberFormat('en-US', {
  style: 'currency',
  currency: 'USD',

  // These options are needed to round to whole numbers if that's what you want.
  //minimumFractionDigits: 0, // (this suffices for whole numbers, but will print 2500.10 as $2,500.1)
  //maximumFractionDigits: 0, // (causes 2500.99 to be printed as $2,501)
});

formatter.format(2500); /* $2,500.00 */

Use undefined in place of the first argument ('en-US' in the example) to use the system locale (the user locale in case the code is running in a browser). Further explanation of the locale code.

Here's a list of the currency codes.

Intl.NumberFormat vs Number.prototype.toLocaleString

A final note comparing this to the older .toLocaleString. They both offer essentially the same functionality. However, toLocaleString in its older incarnations (pre-Intl) does not actually support locales: it uses the system locale. So when debugging old browsers, be sure that you're using the correct version (MDN suggests to check for the existence of Intl). There isn't any need to worry about this at all if you don't care about old browsers or just use the shim.

Also, the performance of both is the same for a single item, but if you have a lot of numbers to format, using Intl.NumberFormat is ~70 times faster. Therefore, it's usually best to use Intl.NumberFormat and instantiate only once per page load. Anyway, here's the equivalent usage of toLocaleString:

(2500).toLocaleString('en-US', {
  style: 'currency',
  currency: 'USD',
}); /* $2,500.00 */

Some notes on browser support and Node.js

Browser support is no longer an issue nowadays with 98% support globally, 99% in the US and 99+% in the EU
There is a shim to support it on fossilized browsers (like Internet Explorer 8), should you really need to
Node.js before v13 only supports en-US out of the box. One solution is to install full-icu, see here for more information
Have a look at CanIUse for more information

Best Answer

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Intl.NumberFormat

Intl.NumberFormat vs Number.prototype.toLocaleString

Some notes on browser support and Node.js

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