Question

What is the best way for converting phone numbers into international format (E.164) using Java?

Given a ‘phone number’ and a country id (let’s say an ISO country code), I would like to convert it into a standard E.164 international format phone number.

I am sure I can do it by hand quite easily – but I would not be sure it would work correctly in all situations.

Which Java framework/library/utility would you recommend to accomplish this?

P.S. The ‘phone number’ could be anything identifiable by the general public – such as

* [phone]
* 1-800-GOT-MILK
* [phone]

that last one is my favourite – it is how some people write their number in the UK and means that you should either use the +44 or you should use the 0.

The E.164 format number should be all numeric, and use the full international country code (e.g.+44)

Answer 1

Google provides a library for working with phone numbers. The same one they use for Android

http://code.google.com/p/libphonenumber/

String swissNumberStr = "044 668 18 00"
PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
try {
  PhoneNumber swissNumberProto = phoneUtil.parse(swissNumberStr, "CH");
} catch (NumberParseException e) {
  System.err.println("NumberParseException was thrown: " + e.toString());
}

// Produces "[phone]"
System.out.println(phoneUtil.format(swissNumberProto, PhoneNumberFormat.INTERNATIONAL));
// Produces "044 668 18 00"
System.out.println(phoneUtil.format(swissNumberProto, PhoneNumberFormat.NATIONAL));
// Produces "[phone]"
System.out.println(phoneUtil.format(swissNumberProto, PhoneNumberFormat.E164));