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Calculating the Number of Days Between Two Dates in java

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Question by neeraj
Submitted on 12/30/2003
Related FAQ: Java Programmers FAQ
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Calculating the Number of Days Between Two Dates in java


Answer by Petru Chifor
Submitted on 2/13/2004
Rating:  Rate this answer: Vote
      GregorianCalendar da1 = new GregorianCalendar(2004,0,1,1,1,1);
      GregorianCalendar da2 = new GregorianCalendar(2004,1,9,8,5,10);
      long d1 = da1.getTime().getTime();
      long d2 = da2.getTime().getTime();
      long difMil = d2-d1;
      long milPerDay = 1000*60*60*24;
      long milPerOra = 1000*60*60;
      long milPerMin = 1000*60;
      long milPerSec = 1000;

      long days = difMil / milPerDay;
      long ore = ( difMil - days*milPerDay ) / milPerOra;
      long min = ( difMil - days*milPerDay - ore*milPerOra ) / milPerMin;
      long sec = ( difMil - days*milPerDay - ore*milPerOra - min*milPerMin ) / milPerSec;
      long mil = ( difMil - days*milPerDay - ore*milPerOra - min*milPerMin - sec*milPerSec );

      System.out.println("days="+days+" ore="+ore+" min="+min+" sec="+sec+" mil="+mil);

 

Answer by DASTAS
Submitted on 4/14/2005
Rating: Not yet rated Rate this answer: Vote
My Answer for those situation:

/****************************************************************************
* Author:  JAVIER A. DASTAS MENDEZ
* NOTE  :  
*  + Functions:
*      no_days(initial_date, end_date)
*        initial_date : STRING
*        end_date     : STRING
*        return  an int value (no of days)
*      rest_of_days(end_date)
*        end_date     : STRING
*        return  an int value (no of days)
*      StrToDate(string_date)
*        string_date  : STRING
*        return  DATE value (format "yyyy-MM-dd")
****************************************************************************/

import java.lang.*;
import java.util.*;
import java.text.*;

public class days_elapse
//  - A CLASS TO CALCULATE THE NUMBER
//    OF DAYS BETWEEN TO DAYS
//  - Convert a STRING to DATE
//    with format "yyyy-MM-dd"
{

  private int no_of_days;
  
  public days_elapse()
  {
  }
  
  public int no_days(String f1, String f2)
  //  Receive two strings with dates
  //  to calculate the number of days
  //  between the to dates
  {
    Date FechaActual = new Date();

    GregorianCalendar tmpDate1 = new GregorianCalendar();
    GregorianCalendar tmpDate2 = new GregorianCalendar();
  
    int days_elapsed = 0;    
        tmpDate1.setTime(StrToDate(f1));
        if (f2.equalsIgnoreCase("null"))  // check if the sencond date is nulls
        {
              tmpDate2.setTime(FechaActual);
        }
        else
        {
            tmpDate2.setTime(StrToDate(f2));            
        }                        
       days_elapsed = calculate(tmpDate1, tmpDate2);
    return days_elapsed;
  }
  
  private int calculate(GregorianCalendar t1, GregorianCalendar t2)
  //  Calculate the number of days between TWO dates.
  {
    int ndays = 0;
   int n;
    
     if (t1.get(t1.YEAR) < t2.get(t2.YEAR))
        {
          ndays += (366 - t1.get(t1.DAY_OF_YEAR));
          
          for ( n = t2.get(t1.YEAR) + 1; n <= t2.get(t2.YEAR) - 1; n++)
          {
              ndays+=365;
          }
        }
      ndays += t2.get(t2.DAY_OF_YEAR);
      
      if (t2.get(t2.YEAR) == t1.get(t1.YEAR))
      {
        ndays =  t1.get(t1.DAY_OF_YEAR) - t2.get(t2.DAY_OF_YEAR);
      
      }      
        
      return ndays;
  }  
  
  public int rest_of_days(String f2)
  //  Calculate the number of days between the CURRENT DATE
  //  and other STRING Date.
  {    
    GregorianCalendar tmpDate1 = new GregorianCalendar();
    GregorianCalendar tmpDate2 = new GregorianCalendar();
  
    int days_elapsed = 0;    

    tmpDate1.setTime(new Date());
    
    tmpDate2.setTime(StrToDate(f2));            
    
    days_elapsed = calculate(tmpDate2, tmpDate1);

    if (days_elapsed < 1)
      days_elapsed = 0;
      
    return days_elapsed;
  }
  
  private Date StrToDate(String f)
  //  Convert a StRING to DATE,
  //  the String format would be
  //  "yyyy-MM-ddd" but not necessary
  {
    Date dFecha = new Date();  
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
        
    try
    {
    dFecha = format.parse(f);
    }
    catch(ParseException e)
    {
      return dFecha;
    }
    
    return dFecha;
  }
  
  public double getNo_Days()
  {
      return no_of_days;
  }
}

 

Answer by slaughters
Submitted on 8/30/2005
Rating: Not yet rated Rate this answer: Vote
Date OldDate = new Date("08/01/2005");
Date TodaysDate = new Date();

long mills_per_day = 1000 * 60 * 60 * 24;

long day_diff = ( TodaysDate.getTime() - OldDate.getTime() ) / mills_per_day;

out.print(day_diff);

 

Answer by S W
Submitted on 11/3/2005
Rating: Not yet rated Rate this answer: Vote
Very great answer to my question.

I have spent hours to learn a useful means for calculating the difference of two dates, however, no solid example shows me the full picture. Thanks to Petru Chifor, you solved my problem instantly!

 

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