Hi all... Hope you're enjoying your time... Today I will explain how to use date-time (date manipulation) in the Java programming language. I was working on a task where I needed to play with time/date. In my other post, I explained the date formatting in C#. Today you will learn the same concept in Java. The 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 and time with the Calendar class. First get the current date and time with Calendar(). [code language="java"] DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss"); Calendar cal = Calendar.getInstance(); System.out.println("Current Date Time : " + dateFormat.format(cal.getTime())); [/code] now you can use following calender date time manipulation function as per your need [code language="java"] //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); [/code] Here is the full source code to show how to modify date time in Java [code language="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())); } } [/code]

Output

Current Date Time : 2010/08/13 10:24:53 Add one day to current date : 2010/08/14 10:24:53 Add one month to current date : 2010/09/13 10:24:53 Add one year to current date : 2011/08/13 10:24:53 Add one hour to current date : 2010/08/13 11:24:53 Add one minute to current date : 2010/08/13 10:25:53 Add one second to current date : 2010/08/13 10:24:54 Subtract one day from current date : 2010/08/12 10:24:53 Subtract one month from current date : 2010/07/13 10:24:53 Subtract one year from current date : 2009/08/13 10:24:53 Subtract one hour from current date : 2010/08/13 09:24:53 Subtract one minute from current date : 2010/08/13 10:23:53 Subtract one second from current date : 2010/08/13 10:24:52 Thanks for your time. free counters