You are misunderstanding and abusing these classes.
Timestamp
& Date
have no time zone but UTC
manipulate on Timezone for java.sql.Timestamp
A java.sql.Timestamp
is always a moment in UTC. No other time zone is involved, only UTC. Ditto for java.util.Date
– always in UTC, no other time zone involved.
So your Question, as quoted above, does not make sense.
Timestamp
& Date
have no “format”
Neither Timestamp
nor Date
have a “format”. They use their own internally defined way to track the date-time. They are not strings, so they have no format. You can generate a String to represent their value in a particular format, but such a String is distinct and separate from the generating object.
java.time
You are using troublesome old date-time classes that wore supplanted years ago by the java.time classes.
Both Timestamp
and Date
are replaced by 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).
Your input is
String input = "2012-06-20 18:22:42.0" ;
That input is nearly compliant with standard ISO 8601 format. To comply fully, replace the SPACE in the middle with a T
.
String input = "2012-06-20 18:22:42.0".replace( " " , "T" ) ;
Parse as a LocalDateTime
because it lacks an indicator of offset-from-UTC or time zone.
LocalDateTime ldt = LocalDateTime.parse( input ) ;
A LocalDateTime
, like your input string, does not represent a moment, is not a point on the timeline. Without the context of a time zone or offset-from-UTC, it has no real meaning. It represents only potential moments along a range of about 26-27 hours.
If you know the intended time zone, apply it to get a ZonedDateTime
object.
ZoneId z = ZoneId.of( "Africa/Tunis" ) ;
ZonedDateTime zdt = ldt.atZone( z ) ;
As for the other formats you mentioned, your Question is not at all clear. Search Stack Overflow for DateTimeFormatter
class to see many examples and discussions of generating/parsing strings with the java.time classes. But first, get clear on the crucial concept that strings are not the date-time objects, and the date-time objects are not strings.
Database
If you were using java.sql.Timestamp
to exchange data with a database, no need for that class anymore. As of JDBC 4.2 and later, you can directly exchange java.time objects with your database.
myPreparedStatement.setObject( … , instant ) ;
…and…
Instant instant = myResultSet.getObject( … , Instant.class ) ;
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.
java.sql.Timestamp
doesn't have a timezone, so you can't change it. – Mark Rotteveel