CODEWITHSUNDEEP
javaandroidunix
Naveen
Naveen

Reputation: 77

Get unix timestamp value from only year in android

How to get Unix timestamp value only for particular year.

I have a situation where in server side for DOB i store only year. So in android i take Age value and then subtract current year with the age and send that year to server. To send that year i need to convert to Unix timestamp because in server side it stores in Unix timestamp format.

Somebody please help what can be done. I saw some links which uses getTime() and divide it by 1000. But that would be whole year with date and month.

Upvotes: 2

Views: 1118

Answers (2)

Basil Bourque
Basil Bourque

Reputation: 339442

java.time

I get current year and i am converting it to integer and then age which user enters. For example, current year is 2014 and he puts age as 20 so his dob year is 1994. I wanted timestamp value of 1994. And i wanted in GMT.

Apparently you want to the moments at each end of a year.

The modern solution uses the java.time classes that supplanted the terrible old legacy date-time classes.

Parse integer from string

First the year. 

String input = "20" ;
integer age = Integer.parseInt( input ) ;

Time zone

Determining a date, and therefore a year, requires a time zone.

A time zone is crucial in determining a date. For any given moment, the date varies around the globe by zone. For example, a few minutes after midnight in Paris France is a new day while still “yesterday” in Montréal Québec.

If no time zone is specified, the JVM implicitly applies its current default time zone. That default may change at any moment during runtime(!), so your results may vary. Better to specify your [desired/expected time zone][2] explicitly as an argument.

Specify a proper time zone name in the format of continent/region, such as America/Montreal, Africa/Casablanca, or Pacific/Auckland. Never use the 2-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!). 

ZoneId z = ZoneId.of( "America/Montreal" ) ;

If you want to use the JVM’s current default time zone, ask for it and pass as an argument. If omitted, the JVM’s current default is applied implicitly. Better to be explicit, as the default may be changed at any moment during runtime by any code in any thread of any app within the JVM.

ZoneId z = ZoneId.systemDefault() ;  // Get JVM’s current default time zone.

Year

Get the current year.

Year currentYear = Year.now( z ) ;

LocalDate & ZonedDateTime

Get the first day of the year as a LocalDate. From that, get the first moment of the day as a ZonedDateTime. A day does not always start at 00:00, so let java.time determine the first moment.

LocalDate firstOfYear = currentYear.atDay( 1 ) ;
ZonedDateTime yearStart = firstOfYear.atStartOfDay( z ) ;

Half-Open

Use Half-Open approach to defining a span-of-time, where beginning is inclusive while the ending is exclusive.

LocalDate firstOfFollowingYear = currentYear.plusYears( 1 ).atDay( 1 ) ;
ZonedDateTime yearStop = firstOfFollowingYear.atStartOfDay( z ) ;

Count-from-epoch

You do not specify what you mean exactly by “Unix timestamp”. I will guess you mean a count of whole seconds since the epoch reference of first moment of 1970 in UTC.

long start = yearStart.toEpochSecond() ;
long stop = yearStop.toEpochSecond() ;

For more discussion, see my Answer to a similar Question.

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.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

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

adboco
adboco

Reputation: 2870

Try this:

Calendar myCal = Calendar.getInstance();
myCal.set(Calendar.YEAR, theYear); // Set the year you want
myCal.set(Calendar.DAY_OF_YEAR, 1);
myCal.set(Calendar.HOUR, 0);
myCal.set(Calendar.MINUTE, 0);
Date theDate = myCal.getTime();

Upvotes: 1

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