Reputation: 2505

Require help for SWT DateTime in Java

I retrieve a Date from the database using the ResultSet rsExpid.

Date joindate = rsExpid.getDate("join_date_ad");
System.out.println(joindate);
int year = joindate.getYear();
System.out.println(year);
int month =joindate.getMonth();
System.out.println(month);
int day = joindate.getDay();
System.out.println(day);
dateTimeJoin4.setDate(year, month, day);

When I print joindate to the console it shows correctly as 2011-08-03, but when I print the year to the console I was amazed to see 111. Similarly printing the month produced 7 and the day resulted in 3.

The variable dateTimeJoin4 is my SWT DateTime. It is not setting any value and it is also not giving any error message. Could please anybody help me on this?

Upvotes: 1

Answers (4)

Basil Bourque

Reputation: 339837

java.time

In modern Java, use java.time classes. Never use the terribly-flawed legacy called such as Date, Calendar, and SimpleDateFormat.

`java.time.LocalDate`

For a date-only value, without time-of-day, and without time zone or offset, use Java class LocalDate. In SQL, define your column as a data type akin to the SQL standard type DATE.

Retrieval:

LocalDate ld = myResultSet.getObject( … , LocalDate.class ) ;

Writing:

myPreparedStatement.setObject( … , ld ) ;

SWT

I do not know SWT. But according to the Javadoc for the SWT widget DateTime, we can pass the year, month, and day as you showed in the Question.

We need to extract the year, month, and day from our LocalDate object. The extraction is easy, by calling getter methods.

mySwtDateTime.setDate( ld.getYear() , ld.getMonthValue() , ld.getDayOfMonth() ) ;

Upvotes: 1

Dinup Kandel

Reputation: 2505

I tried using this method and it worked correctly so this method can be useful to other.

Calendar startCal = Calendar.getInstance();
startCal.setTime(joindate);
int months= startCal.get(Calendar.MONTH);
int years= startCal.get(Calendar.YEAR);
int days= startCal.get(Calendar.DAY_OF_MONTH);
System.out.println(months+1);
System.out.println(years);
System.out.println(days);
dateTimeJoin4.setDate(years, months+1, days);

Upvotes: 2

Jon Skeet

Reputation: 1503080

Chances are you haven't read the documentation for Date.getYear and Date.getMonth:

Returns a value that is the result of subtracting 1900 from the year that contains or begins with the instant in time represented by this Date object, as interpreted in the local time zone.

and

Returns a number representing the month that contains or begins with the instant in time represented by this Date object. The value returned is between 0 and 11, with the value 0 representing January.

respectively. Likewise Date.getDay returns the day of the week, not the day of the month - you want Date.getDate() for that (or preferrably a different API entirely, either Calendar or Joda Time).

This has nothing to do with SWT's DateTime type - after all, you only use that in the last line. When something behaves unusually, your first port of call should be the documentation. SWT's DateTime.setDate method is documented to require a year between 1752 and 9999, so 111 will be confusing it. Admittedly it would have been nice if it had thrown an exception, but even so...

The fact that you're calling deprecated methods should have been a hint to you, although Calendar also uses 0-11 for its months.

Personally I would strongly encourage you to use Joda Time for as much of your date and time work as you can. It's a far superior date and time API to the one built into Java. It's not immediately clear whether it's worth you using it here (if this is all you have to do) but if you're doing anything at all significant (including parsing, formatting or any kind of arithmetic) you should be using it.

Upvotes: 7