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Java - get number of days between dates [duplicate]

This question already has answers here:
Calculating days between two dates with Java
(16 answers)
Closed 5 years ago.
I've got a list of dates in format "yyyy-MM-dd", I'd like to have a number of days between my today date "2017-04-15" and first date from list which is higher than mine today date.

I am assuming that your events are not sorted by date. I am assuming that you can use Java 8. This is one of the tasks that have become so much easier with the java.time classes introduced in Java 8 (and backported to Java 6 and 7).
Use LocalDate.now() to get today’s date.
Iterate through your events, all the time keeping track of the closest future event date. For each event use LocalDate.parse() to convert the event’s date to a LocalDate. The 1-arg parse method fits your format. Compare with today’s date and with the earliest future event date encountered so far; if between, store as the new closest date. Use isAfter() and/or isBefore for the comparisons.
After your loop, you will either know the date or you will know that there are no future events at all. In the former case, use ChronoUnit.DAYS.between() to get the number of days from the current date to the event date.

Solution 1
If you are using joda library, then it will be easy, you can use Days.daysBetween :
Date startDate = ...;
Date endDate = ...;
int nbrDays = Days.daysBetween(new LocalDate(startDate), new LocalDate(endDate)).getDays();
Solution 2
Date startDate = ...;
Date endDate = ...;
Calendar cal = Calendar.getInstance();
cal.setTime(startDate);
int day1 = cal.get(Calendar.DAY_OF_MONTH);
cal.setTime(endDate);
int day2 = cal.get(Calendar.DAY_OF_MONTH);
int nbrDays = day1 - day2;
System.out.println(nbrDays);
You have to import :
import java.util.Calendar;
import java.util.Date;
Solution 3
If your dates are in this format "yyyy-MM-dd" so you can have two dates like this :
String date1 = "1991-07-03";
String date2 = "2017-04-15";
What you should to do, split your dates with - :
String spl1[] = date1.split("-");
String spl2[] = date2.split("-");
Calculate the difference between the two dates :
int year1 = Integer.parseInt(spl1[0]);
int month1 = Integer.parseInt(spl1[1]);
int days1 = Integer.parseInt(spl1[2]);
int year2 = Integer.parseInt(spl2[0]);
int month2 = Integer.parseInt(spl2[1]);
int days2 = Integer.parseInt(spl2[2]);
//make some calculation and in the end you can get the diffidence, this work i will let it for you.

This should solve your problem.
SimpleDateFormat myDateFormat = new SimpleDateFormat("yyyy-MM-dd");
List<Date> dateList = new ArrayList<Date>();
try {
beforeDate = myDateFormat.parse("2016-01-13");
dateList.add(myDateFormat.parse("2016-01-10"));
dateList.add(myDateFormat.parse("2016-01-11"));
dateList.add(myDateFormat.parse("2016-01-12"));
dateList.add(myDateFormat.parse("2016-01-19"));
dateList.add(myDateFormat.parse("2016-01-20"));
dateList.add(myDateFormat.parse("2016-01-21"));
} catch (ParseException e) {
System.out.println(e.getMessage());
}
//add here
boolean check = true;
for(int i = 0; check && i < dateList.size();i++){
if(dateList.get(i).after(beforeDate)){
afterDate = dateList.get(i);
check = false;
}
}
System.out.println(beforeDate+" "+afterDate);
long days = ChronoUnit.DAYS.between(LocalDate.parse(myDateFormat.format(beforeDate)), LocalDate.parse(myDateFormat.format(afterDate)));
if(days>0){
System.out.println(days);
}else{
System.out.println(0-days);
}
if you want to sort dateList then want to get afterDate then use this code after addition of date elements in dateList
Collections.sort(dateList,new Comparator<Date>() {
#Override
public int compare(Date o1, Date o2) {
return o1.compareTo(o2);
}
});
This will allow you to sort dates in ascending order..

get yesterday date from timestamp [duplicate]

This question already has answers here:
Get yesterday's date using Date [duplicate]
(8 answers)
Closed 8 years ago.
I've got an object with a field timestamp with type java.sql.Timestamp;.
And I need to get objects with yesterday date from a collection.
How to get them?
I mean I need something like this
for(int i = 0; i < items.size(); i++) {
(if the items.get(i).date == yesterday_date)
(get object)
}

You can get yesterday's Date by following approach Answered by Jiger Joshi.
And by using new Timestamp(java.util.Date) you can get yesterday's timestamp, you should use Timestamp#equals to equaling two different timestamp.
if (items.get(i).date.equals(getYesterdaytimestamp())){
...
}
And there are something which you must consider while implementing this. Calender#getTime which returns Date object and date object contains date with time, so in that case your equaling date or timestamp must be exactly equals with yesterday's date and time.
If requirement is, it needs to equal just yesterday no not where time is not considerable fact. In that case you need to equals two timestamp after discarding time part.
if (equalsWithYesterday(items.get(i).date)){
...
}
...
public boolean equalsWithYesterday(Timestamp st){
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd"); // Time part has discarded
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
Date yesterday = dateFormat.parse(dateFormat.format(cal.getTime())); // get yesterday's Date without time part
Date srcDate = new Date(st);
Date srcDateWithoutTime =dateFormat.parse(dateFormat.format(srcDate));
return yesterday.equals(srcDateWithoutTime ); // checks src date equals yesterday.
}

You can convert the timestamp object to date object like this:
Date date = new Date(items.get(i).getTime());
or you can simply use method Timestamp#compareTo(Date o)
items.get(i).compareTo(yesterday_date);

I hope you are not interested to compare the time?
Simply use Calendar class to extract the day, month, year etc. from the date and simply compare it.
Use Calendar#get() method to get the specific field from the date object.
How to subtract one day from the current date?
// get Calendar with current date
Calendar cal = Calendar.getInstance();
// get yesterday's date
cal.add(Calendar.DATE, -1);
// get components of yesterday's date
int month = cal.get(Calendar.MONTH) + 1; // 0 for January, 1 for Feb and so on
int day = cal.get(Calendar.DATE);
int year = cal.get(Calendar.YEAR);
// get yesterday's date in milliseconds
long lMillis = cal.getTime().getTime();

How do I figure out whether the current time is in between two times? [duplicate]

This question already has answers here:
How can I determine if a date is between two dates in Java? [duplicate]
(11 answers)
Closed 9 years ago.
I'm trying to write a schedule program in Java and I need to figure out what time it is, and whether the current time is in between two set times. Figuring out the current time is pretty simple, but do you have any suggestions for figuring out whether it is between two times of day. For example, it is 9:33 AM on a Thursday. So I would need to figure out which scheduled section of the week that time corresponds to. How would I go about comparing the time to set periods during the week, for example an Array of sectioned times during a week such as {Monday from 9-10 AM, Tuesday from 3-4 PM, Thursday from 8-11 AM}, and seeing which section of time the current time falls between?

An efficient way to find which period any date lies within would be to have a class;
public class TimePeriod implements Comparable<TimePeriod>{
Date start;
Date end;
//Constructor, getters, setters
boolean isIn(Date date) {
return date.after(start) && date.before(end);
}
public int compareTo(TimePeriod other) {
return start.compareTo(other.start);
}
}
..and then create a sorted list of TimePeriod where you can perform a binary search.
edit:
This might make the binary search easier;
int check(Date date) {
if (isIn(date)) {
return 0;
} else if (start.after(date)) {
return -1;
} else if (end.before(date)) {
return 1;
} else {
throw new IllegalStateException("Time has gone badly wrong");
}
}

If you're using Date Class, you could do it like this
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm");
Date before = sdf.parse("07/05/2012 08:00");
Date after = sdf.parse("07/05/2012 08:30");
Date toCheck = sdf.parse("07/05/2012 08:15");
//is toCheck between the two?
boolean isAvailable = (before.getTime() < toCheck.getTime()) && after.getTime() > toCheck.getTime();
EDITED
As suggested by Jonathan Drapeau you could also use compareTo.
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm");
Date before = sdf.parse("07/05/2012 08:00");
Date after = sdf.parse("07/05/2012 08:30");
Date toCheck = sdf.parse("07/05/2012 08:15");
//is toCheck between the two?
if you want to include the "initial" and "final" date range
boolean isAvailable = before.compareTo(toCheck) >= 0 && after.compareTo(toCheck) <= 0
if you want to exclude the "initial" and "final" date range
boolean isAvailable = before.compareTo(toCheck) > 0 && after.compareTo(toCheck) < 0
You could use it too on Calendar class.
Anyway, i highly recommend you to use Calendar. It's a way precise class
you could check it like this:
Calendar cal1 = Calendar.getInstance(); // for example 12:00:00
Calendar cal2 = Calendar.getInstance(); // for exmaple 12:30:00
Calendar userTime = Calendar.getInstance(); // time to test: 12:15:00
if(user.after(cal1)&& user.before(cal2)){
//...
}
And to initialize and set times to Calendar, check this:
http://www.tutorialspoint.com/java/util/calendar_settime.htm

I would suggest using the Epoch time.
For a definition of Epoch time: http://en.wikipedia.org/wiki/Epoch_time
Basically, its a number of seconds after a specific date, i believe in 1989. If you translate the 3 times (the current time and the 2 times to compare to) in epoch time you can just use > < = etc.
For information on getting epoch time, Try here (has many languages): http://shafiqissani.wordpress.com/2010/09/30/how-to-get-the-current-epoch-time-unix-timestamp/
Unfortunately, my java is lacking or I'd give you some code :)
Edit:
Java epoch time code:
long epoch = System.currentTimeMillis()/1000;
Because my Java is bad and I don't have an interpreter where I am, I can only suggest using this site to help convert the other dates to epoch time: http://www.epochconverter.com/

There is before(Date) and after(Date) method in Date Class.
secondDate.before(firstDate)

If you use Calendar class, it has explicit before() and after() methods:
Calendar startDate = ...
Calendar endData = ...
isBetween = currentDate.after(startDate) && currentDate.before(endDate);

Dates are not getting compared?

I am comparing dates in my android application, how ever for my equal dates, compareTo or equals method returns me that dates are not equal. I have debugged through and I can see both my objects have same values. But some how it is not working. Following is the way I am doing it:
public static boolean compareDates(long deliveryTime, Date date) throws ParseException {
Date deliveryDate = convertLongToDate(deliveryTime);
deliveryDate.setHours(0);
deliveryDate.setMinutes(0);
deliveryDate.setSeconds(0);
if (deliveryDate.equals(date))
{
return true;
}
return false;
}
My date object does not contain time, so I am setting deliverTime's time to 0(zero) as well, so that both objects can have same values. but it does not work. Any help is appreciated. Thanks!

I would create a Date object out of the deliveryTime, and then compare the hours, minutes and seconds. A code is below.
public static boolean compareDates(long deliveryTime, Date date) {
Date d = new Date(deliveryTime);
return(d.getHours() == date.getHours() && d.getMinutes() == date.getMinutes() && d.getSeconds() == date.getSeconds());
}

Would it not be easier to just compare deliveryTime to date.getTime() instead of converting deliveryTime to a Date?
Edit
Since you didn't mention you want to ignore milliseconds, you could do:
(deliveryTime / 1000) == (date.getTime() / 1000)
That should strip out the milliseconds. Alternatively,
Calendar c = Calendar.getInstance();
c.setTime(deliveryTime);
c.set(Calendar.MILLISECOND, 0);
//Clear out the other fields you don't care to compare
Date deliveryDate = c.getTime()

If you make date and deliverydate into date objects, then you can use
date.compareTo(deliveryDate);
This will return: 0 if the dates are the same, a value greater than 0 if date is more recent than deliveryDate, and a value less than 0 if date is before deliveryDate.
To get your dates into date format, you can use something like the following:
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date = sdf.parse(date);
Date deliveryDate = sdf.parse(deliveryTime);

Compare same date using java

The date is selected by the user using a drop down for year, month and day. I have to compare the user entered date with today's date. Basically see if they are the same date. For example
the user entered 02/16/2012. And if today is 02/16/2012 then I have to display a message. How do I do it?
I tried using milliseconds but that gives out wrong results.

And what kind of object are you getting back? String, Calendar, Date? You can get that string and compare it, at least that you think you'll have problems with order YYYY MM DD /// DD MM YYY in that case I suggest to create a custom string based on your spec YYYYMMDD and then compare them.
Date d1 = new Date();
Date d2 = new Date();
String day1 = d1.getYear()+"/"+d1.getMonth()+"/"+d1.getDate();
String day2 = d2.getYear()+"/"+d2.getMonth()+"/"+d2.getDate();
if(day1.equals(day2)){
System.out.println("Same day");
}

Dates in java are moments in time, with a resolution of "to the millisecond". To compare two dates effectively, you need to first set both dates to the "same time" in hours, minutes, seconds, and milliseconds. All of the "setTime" methods in a java.util.Date are depricated, because they don't function correctly for the internationalization and localization concerns.
To "fix" this, a new class was introduced GregorianCalendar
GregorianCalendar cal1 = new GregorianCalendar(2012, 11, 17);
GregorianCalendar cal2 = new GregorianCalendar(2012, 11, 17);
return cal1.equals(cal2); // will return true
The reason that GregorianCalendar works is related to the hours, minutes, seconds, and milliseconds being initialized to zero in the year, month, day constructor. You can attempt to approximate such with java.util.Date by using deprecated methods like setHours(0); however, eventually this will fail due to a lack of setMillis(0). This means that to use the Date format, you need to grab the milliseconds and perform some integer math to set the milliseconds to zero.
date1.setHours(0);
date1.setMinutes(0);
date1.setSeconds(0);
date1.setTime((date1.getTime() / 1000L) * 1000L);
date2.setHours(0);
date2.setMinutes(0);
date2.setSeconds(0);
date2.setTime((date2.getTime() / 1000L) * 1000L);
return date1.equals(date2); // now should do a calendar date only match
Trust me, just use the Calendar / GregorianCalendar class, it's the way forward (until Java adopts something more sophisticated, like joda time.

There is two way you can do it. first one is format both the date in same date format or handle date in string format.
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
String date1 = sdf.format(selectedDate);
String date2 = sdf.format(compareDate);
if(date1.equals(date2)){
}else{
}
Or
Calendar toDate = Calendar.getInstance();
Calendar nowDate = Calendar.getInstance();
toDate.set(<set-year>,<set-month>,<set-date->);
if(!toDate.before(nowDate))
//display your report
else
// don't display the report

Above answers are correct but consider using JodaTime - its much simpler and intuitive API.
You could set DateTime using with* methods and compare them.
Look at this answer