how to save object with sysdate functionality - mysql

Question

i have an object student. then there is a property called expiry date. this is need to be set with the database sysdate + a value(1000).
so how can i save with jpa. can't i do it on the jpa prepared statement query itself?
if i use sql.date is it exactly give the same value as when we are saving as 'sysdate'?
can't i do it with on the query itself?
other properties can be set to the object. but the problem is this expiry date as it needs the sysdate and add another value to it eg: expiry date = sysdate + 1000; how can i do it with jpa prepared statements. please reply me

Answer 1

What about use a seperate query to retrieve sysdate and set it to your object.
I usally create a Clock to handle this:
public interface Clock {
Date now();
}
public class HibernateClock implements Clock {
//use query to retieve the db sysdate
}

Answer 2

You can add it in java itself. Use calendar object to add days.
Calendar expirydate=Calendar.getInstance();
expirydate.add(Calendar.DATE, 1000);
then
expirydate.getTime() will give you expire date object.

Answer 3

Why do you want to use sysdate? Its syntax is database specific and also dependent on the DB-hosting machine's clock, rather than on your application-hosting machine's clock.
Easiest way is to use java.util.Date as the expiryDate's type and the value of new Date(System.currentTimeInMillis() + 1000). Use this value in the field's declaration for featuring it as default value on new Student creation or use it as the value passed to the setter when modifying an existant Student.
public class Student {
...
/**
* Using java.util.Date here. Hibernate knows to convert it automagically to java.sql.Date.
* Set default value to current time + 1 second, if this is your requirement.
*/
private Date expiryDate = new Date(System.currentTimeInMillis() + 1000);
public void setExpiryDate(final Date expiryDate) {
this.expiryDate = expiryDate;
}
...
}