Java Calendar class (java.util.Calendar) is a very useful and handy class in java date time manipulation. here i will demonstrate how to modify date time with calender class.
Get current date time with Calendar()
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
System.out.println("Current Date Time : " + dateFormat.format(cal.getTime()));
Calender date time manipulation function
//Add one day to current date time
cal.add(Calendar.DATE, 1);
//Add one month to current date time
cal.add(Calendar.MONTH, 1);
//Add one year to current date time
cal.add(Calendar.YEAR, 1);
//Add one hour to current date time
cal.add(Calendar.HOUR, 1);
//Add one minute to current date time
cal.add(Calendar.MINUTE, 1);
//Add one second to current date time
cal.add(Calendar.SECOND, 1);
//Subtract one day from current date
cal.add(Calendar.DATE, -1);
//Subtract one month from current date
cal.add(Calendar.MONTH, -1);
//Subtract one year from current date
cal.add(Calendar.YEAR, -1);
//Subtract one hour from current date
cal.add(Calendar.HOUR, -1);
//Subtract one minute from current date
cal.add(Calendar.MINUTE, -1);
//Subtract one second from current date
cal.add(Calendar.SECOND, -1);
Here is the full source code to show how to modify date time in Java
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
public class DateTimeManipulation {
public static void main(String[] args) {
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
//get current date time with Calendar()
Calendar cal = Calendar.getInstance();
System.out.println("Current Date Time : " + dateFormat.format(cal.getTime()));
cal.add(Calendar.DATE, 1);
System.out.println("Add one day to current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.MONTH, 1);
System.out.println("Add one month to current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.YEAR, 1);
System.out.println("Add one year to current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.HOUR, 1);
System.out.println("Add one hour to current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.MINUTE, 1);
System.out.println("Add one minute to current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.SECOND, 1);
System.out.println("Add one second to current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
System.out.println("Subtract one day from current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.MONTH, -1);
System.out.println("Subtract one month from current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.YEAR, -1);
System.out.println("Subtract one year from current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.HOUR, -1);
System.out.println("Subtract one hour from current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.MINUTE, -1);
System.out.println("Subtract one minute from current date : " + dateFormat.format(cal.getTime()));
cal = Calendar.getInstance();
cal.add(Calendar.SECOND, -1);
System.out.println("Subtract one second from current date : " + dateFormat.format(cal.getTime()));
}
}
Output
Current Date Time : 2008/12/28 10:24:53
Add one day to current date : 2008/12/29 10:24:53
Add one month to current date : 2009/01/28 10:24:53
Add one year to current date : 2009/12/28 10:24:53
Add one hour to current date : 2008/12/28 11:24:53
Add one minute to current date : 2008/12/28 10:25:53
Add one second to current date : 2008/12/28 10:24:54
Subtract one day from current date : 2008/12/27 10:24:53
Subtract one month from current date : 2008/11/28 10:24:53
Subtract one year from current date : 2007/12/28 10:24:53
Subtract one hour from current date : 2008/12/28 09:24:53
Subtract one minute from current date : 2008/12/28 10:23:53
Subtract one second from current date : 2008/12/28 10:24:52
I need program to set manual date and calculate time increment like as second, minute hours , date including leap year and output show in eclipse console
Trying to write a HTML Date Header, http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html I arrived this page …
… and thanks to the combination of SimpleDateFormat (to which I assign the RFC “mandatory” timezone) and an instance of Calendar we can obtain an automatic translation of hour local time to absolute GMT time …
public static String getHTMLDateHeader(){
// http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html
DateFormat dateFormat = new SimpleDateFormat(“EEE, dd MMM YYY HH:mm:ss z”, Locale.US);
dateFormat.setTimeZone(TimeZone.getTimeZone(“GMT”));
Calendar localDateTime = Calendar.getInstance();
return dateFormat.format(localDateTime.getTime());
}
Thanks everybody!
I am a beginner and i work with datas . I have this kind of data “962409600000” and i have to change this data to datetime format and the result was “2000-07-01T05:45:00.000+05:45”.
Please can you help me i need only the date 2000-07-01.
Thanks
recently, working on a big project I loved light-weight Joda-Time framework, which lives here http://joda-time.sourceforge.net/userguide.html#Manipulating_DateTimes
This information is very helpful.
Thank you a million times
Very helpful. Thanks a bunch for posting this.
udhay. u may use as follows;
z = 10;
String dt = “2011-02-10”; // Start date
SimpleDateFormat sdf = new SimpleDateFormat(“yyyy-MM-dd”);
Calendar c = Calendar.getInstance();
c.setTime(sdf.parse(dt));
c.add(Calendar.DATE, z); // number of days to add
dt = sdf.format(c.getTime());
Very useful. Used in an application already. Thnx a lot to author to share.
Date cant be modified. But it could be used to compare dates by using getTimeInMillis().
this is Calender “cal”
how to modifiy with Date “d”??