How to convert unix timestamp into Date - sql

Question

I am trying to convert Unix time stamp into date
final DateTimeFormatter formatter =
DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
final String startdate = Instant.ofEpochSecond(Long.parseLong(requestVO.getStartDate().toString()))
.atZone(ZoneId.of("GMT-4"))
.format(formatter);
final String enddate = Instant.ofEpochSecond(Long.parseLong(requestVO.getEndDate().toString()))
.atZone(ZoneId.of("GMT-4"))
.format(formatter);
above is what I have tried for the format of date Mentioned in DateTimeFormatter and requestVO.getStartDate() is giving Date type value.I am applying the startDate and endDate in sql query Like below
and ceo.erx_date between '"+startdate+"' and '"+enddate+"'
No compilation errors getting But, giving number format exception.

Answer 1

If requestVo.getStartDate() returns a Date object, your error is here:
Long.parseLong(requestVo.getStartDate())
As the documentation says, Long.parseLong(String) throws
NumberFormatException - if the string does not contain a parsable long.
Try this:
Long.parseLong(requestVo.getStartDate().getTime())
In every case two things:
Take care from NullPointerException: check if your date is null or not
Use preparedStatement and not string concatenation when write e query in Java
There are at least two reasons to use PreparedStatement instead of Statement:
They are faster then simple Statement: because Statement are compiled and execute every time, but PreparedStatment are compiled once
In case of PreparedStatement you are safe from the point of view of SQL injection

Answer 2

tl;dr
myJavaUtilDate // The terrible `java.util.Date` class is the legacy way to represent a moment in UTC.
.toInstant() // `Instant` is modern way to represent a moment in UTC.
.atZone( // Adjust from UTC to some time zone.
ZoneId.of( "America/Martinique" ) // Specify the time zone you had in mind for an offset of four hours behind UTC.
) // Returns a `ZonedDateTime` object.
.format( // Generate text representing the value of our `ZonedDateTime` object's content.
DateTimeFormatter.ISO_LOCAL_DATE_TIME // A predefined formatter per ISO 8601 that omits any indication of time zone or offset-from-UTC.
)
.replace(
"T" , // Standard ISO 8601 formats use a `T` between the date and time-of-day portions.
" "
) // Returns a `String`.
java.util.Date::toInstant
requestVO.getStartDate() is giving Date type value.
You are working too hard.
Convert the terrible Date class object to its modern replacement, Instant. Notice how the legacy classes were given new methods for conversion to/from the modern java.time classes. Look for to… & from… methods on the old classes. In this case, Date::toInstant.
Instant instant = myJavaUtilDate.toInstant() ;
Zone versus offset
.atZone(ZoneId.of("GMT-4"))
Nope, -4 is not a time zone. That is an offset.
An offset-from-UTC is merely a number of hours-minutes-seconds ahead or behind the prime meridian.
A time zone is much more. A time zone is a history of the past, present, and future changes in offset used by the people of a particular region. A time zone carries a name in format of Continent/Region such as Asia/Kolkata or Pacific/Auckland.
Better to use a time zone than a mere offset. For one thing, you may be wrong about the offset. By using an time zone, java.time will determine the offset in effect at your intended moment.
Zone for offset of four hours behind UTC
Perhaps by -4 you have in mind a time zone such as America/Martinique, America/Aruba, or America/Puerto_Rico.
ZoneId z = ZoneId.of( "America/Puerto_Rico" ) ;
Instant + ZoneId ➡ ZonedDateTime
Apply that ZoneId to produce a ZonedDateTime object. Same moment, different wall-clock time.
ZonedDateTime zdt = instant.atZone( z ) ;
Generating text
Produce a string in standard ISO 8601 format, wisely extended to append the name of the zone in square brackets.
String output = zdt.toString() ;
But you wanted a format similar to ISO 8601, but without the T in the middle and with no indicator of offset/zone. I do not recommend reporting a moment without representing the time zone or offset. But if you insist:
String output =
zdt
.format( DateTimeFormatter.ISO_LOCAL_DATE_TIME )
.replace( "T" , " " )
;