Java日期和标准格式

Question

As per this C# code from Mircrosoft there is a standard date format such as this:

//       R: Sun, 15 Jun 2008 21:15:07 GMT 

My C# code uses "r" like so:

webRequest.Date.ToUniversalTime().ToString("r")

How can I create a standard date format like this in Java?

I have this so far:

this.timestamp = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss z").format(new Date());

But, I don't know if I should try to write something that will match it or if there is a better way. My fear is that I will make a mistake and certain dates won't work.

Answer 1

How can I create a standard date format like this in Java?

Look at the documentation for the r format :

The custom format string is "ddd, dd MMM yyyy HH':'mm':'ss 'GMT'". When this standard format specifier is used, the formatting or parsing operation always uses the invariant culture.

[...] Therefore, the application must convert the date and time value to UTC before it performs the formatting operation

So you translate that custom format string into SimpleDateFormat , *and make sure you specify the time zone (UTC) and locale (US English is close enough to the invariant culture):

DateFormat format = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss 'GMT'",
                                         Locale.US);
format.setTimeZone(TimeZone.getTimeZone("UTC"));
String text = format.format(date);

That's if you want to match the format from .NET's r format. Personally I'd go with an ISO-8601 format instead, eg

DateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
                                         Locale.US);
format.setTimeZone(TimeZone.getTimeZone("UTC"));