Subtracting dates and get difference in days.How to subtract them?

Question

can anyone tell how to subtract string "after" from "today" to get days difference.

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


public class Main {
public static void main(String args[]){


SimpleDateFormat sdf=new SimpleDateFormat("yyyy/MM/dd");
Calendar cal=Calendar.getInstance();
String today=sdf.format(cal.getTime());
System.out.println(today);
cal.add(Calendar.DATE, 20);
String After=sdf.format(cal.getTime());
System.out.println(After);

}
}

http://stackoverflow.com/questions/13037654/subtract-two-dates-in-java seems related to this. — WannaBeCoder, Nov 11 '14 at 05:55
[Example using JodaTime](http://stackoverflow.com/questions/12851934/how-to-find-difference-between-two-joda-time-datetimes-in-minutes/12852021#12852021) — MadProgrammer, Nov 11 '14 at 05:58
[JodaTime AND Java 8 Time API example](http://stackoverflow.com/questions/25255811/start-date-and-end-date-between-two-dates/25255894#25255894) — MadProgrammer, Nov 11 '14 at 05:58
@amitbhardwaj I'd agree with, but that's only half the question... — MadProgrammer, Nov 11 '14 at 06:01
I deleted it because of @MadProgrammer comment. I guess you should cross verify and check if it there is a better way. — WannaBeCoder, Nov 11 '14 at 06:05
sure @WannaBeCoder but i only need a rough guess.. but for those who need accurate result they should'nt do this — Sharan Sondhi, Nov 11 '14 at 06:07
@MadProgrammer agree but the OP is also not clear what is the diff between 8 march 11 pm to 10 march 2 am he want this as 1 day or the real diff is 3 days — amit bhardwaj, Nov 11 '14 at 06:07
@amitbhardwaj Unfortunately, that's where the OP will need to use the values returned by `Duration` or `Period` to make their choices... ;) — MadProgrammer, Nov 11 '14 at 06:12
@MadProgrammer unfortunately `Period` class is in java 8 only so if he is using earlier version he is restricted to use `Duration` — amit bhardwaj, Nov 11 '14 at 06:17
@amitbhardwaj There's a `Period` and `Duration` class in JodaTime... — MadProgrammer, Nov 11 '14 at 06:20

Subhrajyoti Majumder · Answer 1 · 2014-11-11T06:37:00.233

It would be easier with java8 where you dont need to subtract long values represent of date and change back to days, hours and minutes.

Date today= LocalDate.now();
Date futureDate = LocalDate.now().plusDays(1);
long days = Period.between(today, futureDate).getDays();

Period & LocalDate class are available in #java8

LocalDate docs

LocalDate is an immutable date-time object that represents a date, often viewed as year-month-day. Other date fields, such as day-of-year, day-of-week and week-of-year, can also be accessed. For example, the value "2nd October 2007" can be stored in a LocalDate.

If you are not using java8, use joda-time library's org.joda.time.Days utility to calculate this

Days day = Days.daysBetween(startDate, endDate);
int days = d.getDays();

If you're up to it and want to add an example using JodaTime, I'll delete my answer +1 to you though — MadProgrammer, Nov 11 '14 at 06:14

score 3 · Answer 2 · answered Nov 11 '14 at 06:10

Using JodaTime, in case you don't have Java 8

String timeValue = "2014/11/11";
DateTimeFormatter parseFormat = new DateTimeFormatterBuilder().appendPattern("yyyy/MM/dd").toFormatter();
LocalDate startDate = LocalDate.parse(timeValue, parseFormat);
LocalDate endDate = startDate.plusDays(20);

System.out.println(startDate + "; " + endDate);

Period p = new Period(startDate, endDate);
System.out.println("Days = " + p.getDays());
System.out.println("Weeks = " + p.getWeeks());
System.out.println("Months = " + p.getMonths());

Which outputs...

2014-11-11; 2014-12-01
Days = 6
Weeks = 2
Months = 0

score 0 · Answer 3 · answered Nov 11 '14 at 08:33

try this...

May it helps you.

import java.util.Date;
import java.util.GregorianCalendar;

// compute the difference between two dates.

public class DateDiff {
  public static void main(String[] av) {
    /** The date at the end of the last century */
    Date d1 = new GregorianCalendar(2010, 10, 10, 11, 59).getTime();

    /** Today's date */
    Date today = new Date();

    // Get msec from each, and subtract.
    long diff = today.getTime() - d1.getTime();

    System.out.println("The 21st century (up to " + today + ") is "
        + (diff / (1000 * 60 * 60 * 24)) + " days old.");
  }
}

score -1 · Answer 4 · answered Nov 11 '14 at 05:59

This may help You..

SimpleDateFormat sdf=new SimpleDateFormat("yyyy/MM/dd");
    Calendar cal=Calendar.getInstance();
    String today=sdf.format(cal.getTime());
    System.out.println(today);

    cal.add(Calendar.DATE, 20);
    String After=sdf.format(cal.getTime());
    System.out.println(After);

    Date d1 = null;
    Date d2 = null;

    SimpleDateFormat format = new SimpleDateFormat("yyyy/MM/dd");

    try {
        d1 = format.parse(today);
        d2 = format.parse(After);
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    long diff = d2.getTime() - d1.getTime();

    long diffDays = diff / (24 * 60 * 60 * 1000);

    System.out.println("Difference is "+diffDays+" Days");

No, never do this. There are to many variances in how date/time works (leap years, century and millennium boundaries) to simply subtract the millisecond offsets of two dates — MadProgrammer, Nov 11 '14 at 06:00

Subtracting dates and get difference in days.How to subtract them?

4 Answers4

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