Java 8 Setting global time formatters

Question

I want to set my own DateTimeFormatter as the global formatter. When I do the following line:

ZonedDateTime.now();

I get:

2016-03-30T08:58:54.180-06:00[America/Chicago]

If I do this:

ZonedDateTime.now().format(DateTimeFormatter.RFC_1123_DATE_TIME)

I get:

Wed, 30 Mar 2016 9:00:06 -0600

I want what's printed above but with am/pm so I made my custom formatter and printed out the time like so:

DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss a Z");

ZonedDateTime.now().format(FORMATTER);

Which gave me:

Wed, 30 Mar 2016 9:00:06 AM -0600

But I use this .now() method everywhere for logging purposes and I dont want to define the formatter everywhere in the code. Is there a way to configure the formatter as the default format to use when calling the .now() method? I'm thinking like spring bean configuration method or something.....

Answer 1

You could simply declare a constant in a class:

class UtilsOrWhatever {
  public static final DateTimeFormater RFC_1123_DATE_TIME_AM_PM = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy hh:mm:ss a Z");
}

and simply use in your code:

ZonedDateTime.now().format(RFC_1123_DATE_TIME_AM_PM); //needs a static import

Alternatively, with pure Java EE 7, you could create a DateTimeFormatter Producer with @Produces and then simply @Inject it.

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.inject.Produces;

@ApplicationScoped
public class RfcFormatterProducer {
  @Produces
  private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy hh:mm:ss a Z");
}

In your code:

@Inject DateTimeFormatter rfc;

You could also give it a name like in the link above if you have several formatters.