Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
Solved

# How to calculate the number of days between two Dates?

Posted on 2009-05-07
Medium Priority
1,901 Views
I'm trying to write a function that will calculate the number of days that exist between two dates,  but have been unable to come up with an adequete solution thus far. In the reasearch that I've done, I've seen some methods convert the dates to milliseconds, subtract, then convert back. In others, they've incrimented a count variable, and simple added days to the earlier date until the two dates matched. Unfortunately, neither of these methods seems completely accurate under all conditions, nor do they seem as elegant as you'd hope them to be.

How have you done this calculation before? Is there a common library or standard function that's commonly used for this calculation?

0
Question by:MehtaJasmin
[X]
###### Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

• Help others & share knowledge
• Earn cash & points
• 3
• 2
• 2
• +1

LVL 86

Expert Comment

ID: 24324928
0

LVL 16

Expert Comment

ID: 24324931
0

LVL 92

Expert Comment

ID: 24332244
the problem is more in the definition of what you mean by the number of days between two dates. Once that is defined then implementation is generally straight forward. Using a Calendar for the arithmetic is the standard way, and there are also libraries around.

So what is your definition of the number of days between 2 dates?

0

Author Comment

ID: 24335002
My requirement is, if I pass dateA and dateB to the some java method /  API, it should return me how many days they are apart. It should consider if they in the same year/leap year etc. Basically I am coding for password expiry logic where I need to check that last time user has updated password, has it been 60 days yet. If current date is exceeding the 60 day period of validity then I need to prompt user to change the password.

I have dig in to java.util.Calendar API but could not find appropriate method. Also tried writing test program using DateUtils of commons package with getFragmentInDays() and iterator(java.util.Calendar focus,  int rangeStyle). But looks like I need to write quite a bit of math around iterator() to get the result out. So I was looking for any straight api / jar available for my need.

Hope this defines the question better.

Hope this clears the question.
0

LVL 92

Accepted Solution

objects earned 1000 total points
ID: 24335051
Easiest way to do that is as well (or instead of) storing the last updated date, you store the expiry date. Then you just have to check if the current date is after the expiry date.
And if you don't store it you can just use the Calendar class to add the 60 day period to the last updated date and then compare with current date. Much simpler that calculating differences which is messy.

0

LVL 86

Expert Comment

ID: 24335080
``````final int TIME_OUT_DURATION = 1000 * 60 * 60 * 24 * 60;
boolean needToChangePassword = (d1.getTime() - d2.getTime()) > TIME_OUT_DURATION;
``````
0

Author Closing Comment

ID: 31580092
Thanks! Actually had the same idea about the time you posted it. It's a much easier solution to our exact situation than attempting to calculate the time between two arbitrary dates. Thanks again!
0

LVL 92

Expert Comment

ID: 24353273
thanks mate, let me know if you need any other help.

0

## Featured Post

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This was posted to the Netbeans forum a Feb, 2010 and I also sent it to Verisign. Who didn't help much in my struggles to get my application signed. ------------------------- Start The idea here is to target your cell phones with the correctâ€¦
In this post we will learn different types of Android Layout and some basics of an Android App.
Viewers learn how to read error messages and identify possible mistakes that could cause hours of frustration. Coding is as much about debugging your code as it is about writing it. Define Error Message: Line Numbers: Type of Error: Break Downâ€¦
Viewers will learn about arithmetic and Boolean expressions in Java and the logical operators used to create Boolean expressions. We will cover the symbols used for arithmetic expressions and define each logical operator and how to use them in Booleâ€¦
###### Suggested Courses
Course of the Month10 days, 12 hours left to enroll