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I am trying to save a java.util.Date from an application to my SQL Server database using JDBC.

When I convert the java.util.Date to a java.sql.Date using the method below, it truncates the time part.

java.sql.Date javaSqlExpiryDate = new java.sql.Date(javaUtilExpiryDate.getTime());
System.out.println("javaUtilExpiryDate: " + javaUtilExpiryDate.toString());
System.out.println("javaSqlExpiryDate: " + javaSqlExpiryDate.toString());

The Console window reports the output as:

javaUtilExpiryDate: Thu Sep 01 18:19:08 IST 2016

javaSqlExpiryDate: 2016-09-01

How do I get it to retain the time part as well?

Water Cooler v2
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    Do you really need to convert it, if loosing the time part is not what you want? Why not use the java.util.Date directly in your jdbc call? – stenix Sep 01 '16 at 12:01
  • @stenix I checked the overloads of the `PreparedStatement.setDate()` method and none of them seem to want a `java.util.Date`. They all work with `java.sql.*` types. – Water Cooler v2 Sep 01 '16 at 12:47
  • FYI, you are using the troublesome old legacy date-time classes. Now supplanted by the [java.time](http://docs.oracle.com/javase/8/docs/api/java/time/package-summary.html) classes. In JDBC 4.2 and later you may be able to pass/fetch java.time objects directly via `setObject` and `getObject` methods without going through java.sql types. If not, look for new conversion methods added to the old classes. – Basil Bourque Sep 01 '16 at 21:09

3 Answers3

6

Yes, that's the expected and documented behavior.

Quote from the JavaDocs

To conform with the definition of SQL DATE, the millisecond values wrapped by a java.sql.Date instance must be 'normalized' by setting the hours, minutes, seconds, and milliseconds to zero in the particular time zone with which the instance is associated.

If you want to keep the time, you need to use java.sql.Timestamp (especially if the column in the database is defined as datetime).

  • Thank you. I am using the JDBC `PreparedStatement` to parameterize the SQL. That guy needs a `java.sql.Date`, so I how do I get from a `java.sql.Timestamp` to a `java.sql.Date`? – Water Cooler v2 Sep 01 '16 at 12:00
  • @WaterCoolerv2 You can't. You **have** to use `java.sql.Timestamp` and `PreparedStatement.setTimestamp()` –  Sep 01 '16 at 12:01
  • Yes, thank you. I just saw that. 6 more minutes before I can mark this as the right answer. – Water Cooler v2 Sep 01 '16 at 12:02
0

Just change your import from java.sql.Date TO java.sql.Timestamp

Amy
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0

tl;dr

myPreparedObject.setObject(
    1 ,
    myJavaUtilDate.toInstant()  // Convert legacy object to modern java.time object, `Instant`.
)

Details

The other Answers are correct. The java.util.Date class represents a date and a time-of-day in UTC. The java.sql.Date represents only a date, without the time-of-day. Well, actually, the java.sql.Date pretends to represent only a date but actually, as a badly-designed hack, subclasses the java.util.Date class and therefore does have a time-of-day. Confusing? Yes. One of many reasons to avoid these awful old legacy classes.

Now we have a better way, the java.time classes.

java.time

In the old days you would convert your java.util.Date object to a java.sql.Timestamp.

Now, with a JDBC driver supporting JDBC 4.2 and later, you can send your java.time objects directly to/from the database. No need for either the java.util nor java.sql classes, just stick with java.time classes.

If you have to interface with old code using java.util.Date, convert to java.time.Instant using new methods added to the old classes.

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). 

Instant instant = myJavaUtilDate.toInstant() ;

Exchange an Instant with the database via PreparedStatement::setObject and ResultSet::getObject.

myPreparedStatement.setObject( … , instant ) ;

And…

Instant instant = myResultSet.getObject( … , Instant.class ) ;

To see this moment through some other time zone than UTC, apply a ZoneId to get a ZonedDateTime.

ZoneId z = ZoneId.of( "America/Montreal" ) ;
ZonedDateTime zdt = instant.atZone( z ) ;

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.

Basil Bourque
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