CODEWITHSUNDEEP
java
Lennie
Lennie

Reputation: 2069

Weird Date Format To Java Date

I got the following date format that I get from an API (Yes I tried to get them to change the API... dailywtf story):

\/Date(1310481956000+0200)\/

How can I convert this into a Java Date? (java.util.Date)

This comes from a .NET JSON web service.

Upvotes: 2

Views: 2214

Answers (4)

Basil Bourque
Basil Bourque

Reputation: 338181

tl;dr

Instant.ofEpochMilli( 
    java.lang.Long.parseLong( "1310481956000" )
).atOffset( ZoneOffset.of( "+0200" ) )

Using java.time

The accepted Answer is correct but outdated. The modern way to handle this is through the java.time classes.

The input is ambiguous. Is it a count from the Unix epoch reference date-time of first moment of 1970 in UTC 1970-01-01T00:00:00:Z and then adjusted by two hours ahead of UTC? If so, this example code seen here works.

First parse that input number as a Instant. The Instant class represents a moment on the timeline in UTC with a resolution of nanoseconds (up to nine (9) digits of a decimal fraction).

Extract the first portion of your string and parse as a long. 

long millisSinceEpoch = java.lang.Long.parseLong( "1310481956000" );
Instant instant = Instant.ofEpochMilli( millisSinceEpoch );

instant.toString(): 2011-07-12T14:45:56Z

Extract the last portion of your string and parse as a ZoneOffset.

ZoneOffset offset = ZoneOffset.of( "+0200" );

Apply the offset to the Instant to get an OffsetDateTime.

OffsetDateTime odt = instant.atOffset( offset );

odt.toString(): 2011-07-12T16:45:56+02:00

Note that an offset-from-UTC is not a time zone. A zone is an offset plus a set of rules for handling anomalies such as Daylight Saving Time (DST).

Avoid java.util.Date whenever possible. But if you must use one, you can convert to/from java.time. Look to new conversion methods added to the old classes.

java.util.Date d = java.util.Date.from( odt.toInstant() );

d.toString(): Tue Jul 12 14:45:56 GMT 2011

See live code at IdeOne.com covering this entire example.

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Upvotes: 0

Michael J. Lee
Michael J. Lee

Reputation: 12396

You'll have to get the format from the API provider but it seems like a epoch + an offset for time zones. To convert it you could try.

final String fromAPI = "1310481956000+0200"
final String epochTime = fromAPI.substring(0, fromAPI.indexOf("+"));
final String timeZoneOffSet = fromAPI.substring(fromAPI.indexOf("+"), fromAPI.size());

Date date = new Date(Long.parseLong(epochTime));

Notice i'm not doing anything with the time zone (if that's what it is). You'll have to deal with that but this should get you on the right path.

Upvotes: 1

Alistair A. Israel
Alistair A. Israel

Reputation: 6567

Without knowing what the date/time string stands for, let me make a guess.

The 1310481956000 looks to be milliseconds after epoch, and the +0200 an offset relative to GMT.

The following code seem to indicate it as well:

final TimeZone tz = TimeZone.getTimeZone("GMT+0200");
final Calendar cal = Calendar.getInstance(tz);
cal.setTimeInMillis(1310481956000L);
final SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
f.setTimeZone(tz);
System.out.println(f.format(cal.getTime()));

Prints 2011-07-12 16:45:56 GMT+02:00

Upvotes: 9

Stephen C
Stephen C

Reputation: 718688

How can I convert this into a Java Date? (java.util.Date)

First, get "them" to clearly and precisely tell you exactly what that date format means. (If they won't or can't you could guess; see below.)

Next write a custom parser to parse the String and extract the information content.

Finally, convert the information content into a form that matches one of the Date constructors and create an instance.

My guess is that the 1310481956000 part is the number of milliseconds since the UNIX epoch (1970/01/01T00:00) and that the 0200 represents a timezone offset of 2 hours (MET?). However, you shouldn't rely on a guess. Get "them" to give you the specification, or at least a number of examples and the actual times/timezones that they correspond to.

Upvotes: 2

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