Number of weeks between two dates

Hi,

How to find number of weeks between two dates?

Regards
Mah

Hi,
try having a look at the GregorianCalendar class in the java.util package. I has a number of useful methods that will help you do what you want.

DD

Here is a DateDifference class I pick up along the way.

import java.util.*;
import java.text.*;
public class DateDiff {
   // Test code takes two dates as command-line args...
   public static void main(String[] args) {
      DateDiff dd = new DateDiff();
      Date then = null, now = null;
      DateFormat df = DateFormat.getInstance();
      df.setTimeZone( TimeZone.getDefault() );
      if (args.length < 2) {
         String pattern = ((SimpleDateFormat)df).toLocalizedPattern();
         
         System.out.println("Usage: Enter two dates in this format: " 
                          + pattern.substring( 0, pattern.indexOf(' '))
);
         System.exit(0);
      } else {
         try {
            then = df.parse( args[0] + " 12:00 PM" );
            now = df.parse( args[1] + " 12:00 PM" );
         } catch ( ParseException e ) {
            System.out.println("Couldn't parse date: " + e );
            System.exit(1);
         } /* endcatch */
      } /* endif */
      
      // Now we have two Date objects.  Use various "units" to
      //  do the date math: days, weeks, months and years...
      long diff = dd.getDateDiff( now, then, Calendar.DATE );
      System.out.println("Interval in days: " + diff );
 
      diff = dd.getDateDiff( now, then, Calendar.WEEK_OF_YEAR );
      System.out.println("Interval in weeks: " + diff );
 
      diff = dd.getDateDiff( now, then, Calendar.MONTH );
      System.out.println("Interval in months: " + diff );
 
      diff = dd.getDateDiff( now, then, Calendar.YEAR );
      System.out.println("Interval in years: " + diff );
   }
 
   // Use one of the constants from Calendar, e.g. DATE, WEEK_OF_YEAR,
   //  or MONTH, as the calUnit variable.  Supply two Date objects.
   //  This method returns the number of days, weeks, months, etc.
   //  between the two dates.  In other words it returns the result of
   //  subtracting two dates as the number of days, weeks, months, etc.
   long getDateDiff( Date d1, Date d2, int calUnit ) {
      if( d1.after(d2) ) {    // make sure d1 < d2, else swap them
         Date temp = d1;
         d1 = d2;
         d2 = temp;
      }
      GregorianCalendar c1 = new GregorianCalendar();
      c1.setTime(d1);
      GregorianCalendar c2 = new GregorianCalendar();
      c2.setTime(d2);
      for( long i=1; ; i++ ) {         
         c1.add( calUnit, 1 );   // add one day, week, year, etc.
         if( c1.after(c2) )
            return i-1;
      }
   }
}

http://faq.javaranch.com/view?JavaDatesFaq

Hi friends,

Thanks for reply

Regards
mah