Recommended date format for REST API

I'm writing a app that exposes a REST API. Some of the query parameters will be date/time (accurate to second), and some of the responses will be timestamps (accurate to millisecond).

The API implementation on the server is in Java. The client apps can be anything - java, javascript, .NET. The API returns XML or JSON data. Date/Time data is stored in a Oracle database.

Does anyone have recommendations, based on prior pain, of what the best format format is for passing these date/time values. I'm thinking myself to just use a good old fashioned long to store the number of milliseconds since January 1, 1970, 00:00:00 GMT.

Edit The date range covered in the API is for real time events, so there will be nothing before 2010, and (setting myself up for abuse here) nothing after 2038.

I guess best would be determined by

a) Wide variety of languages support converting this long into internal date object, without havi开发者_Python百科ng to write code to do it.

b) Lowest CPU overhead (on server app)

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ISO 8601 all the way

Using any epoch-based method means you are bound to the range (in most systems) of a signed 32-bit INT (1901-12-13T20:45:52+00:00 through 2038-01-19T03:14:07+00:00) which, is really more of a timestamp than a date, since it can't handle far-reaching historical or future dates.