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Java date and calendar classes Posted by jill (jill), 13 December 2004 I need to get a date from an (oracle) database, call it startdate, then get from another table a number of days, a number of hours and a number of minutes and add these to startdate to get a new date and time, call it session. Then I have to store 'session' back in the database. I am very new to Java, and struggling - I think I have to use the calendar class to do the addition - but can you point me to a nice easy to follow example? Also what is the difference between the java.util.date class and the java.sql.date class? TIA for any help Jill Posted by admin (Graham Ellis), 14 December 2004 Dates seem to be over-featured and over-complex in Java:The java.util.Date class has been largely deprecated, but does include a few useful methods. It has been largely replaced by the java.util.Calendar class. To take a date and move forward from it, I would Calendar demo = Calendar.getInstance(); demo.set (appropriate parameters); long now = demo.getTimeinMillis; long finish = perform maths on "now" to set end time demo.setTimeinMillis(finish) This is "pseudocode" ... and I'm not near an appropriate system to test with, but hopefully it may point you in a reasonable direction. The java.sql.Date class deals with date objects to and from SQL databases - so you may need to get involved with that too! Posted by jill (jill), 14 December 2004 Thanks, but I am still stuck! I can get the date out of the database with Date thisdate = resultset.getDate("field") But how do I get that into the Calendar instance? How do I convert the date into milliseconds? In your line demo.set (appropriate parameters); how do I get the parameters, that is without using deprecated methods? TIA Jill Posted by jill (jill), 14 December 2004 Further to my last posting - I just found calendar.setTime(date) which I think is going to get me a bit further. Sorry Jill Posted by jill (jill), 14 December 2004 Getting a bit further - a piece of code which I do not understand seems to be able to get me a java.sql.Date from a calendar namelyjava.sql.Date jsqlD = new java.sql.Date(cal.getTime().getTime() ); So don't worry, and thanks for the input - I will struggle on. Jill Posted by admin (Graham Ellis), 14 December 2004 OK ... do follow up if you hit another wall, and I'll see if I can shed further light. This is a heavy week though ... and virtually all my machines are locked away overnight on site in Oxford so I can't experiment as much as usual.This page is a thread posted to the opentalk forum
at www.opentalk.org.uk and
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