Karthi Krazz Karthi Krazz - 3 months ago 8
Java Question

Calculating the time difference between two time stamp object - java

I am having java.sql.date and java.sql.time objects, I need to find the time duration between the dates.

So i am creating java.sql.timestamp object by using above date and time object

Timestamp timestamp1 = new Timestamp(StartDate.getYear(),
StartDate.getMonth(), StartDate.getDay(),
StartTime.getHours(), StartTime.getMinutes(), 00,
00);


Here is mycode

String date = "2010-01-05";
SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
java.util.Date date3 = null;
try {
date3 = sdf1.parse(date);
} catch (ParseException e) {
e.printStackTrace();
}
Date StartDate = new Date(date3.getTime());
System.out.println("Date " + StartDate);

String date2 = "2010-01-06";
java.util.Date date4 = null;
try {
date4 = sdf1.parse(date2);
} catch (ParseException exception) {
exception.printStackTrace();
}
Date EndDate = new Date(date4.getTime());
System.out.println("Date " + EndDate);

String time = "01:00";
DateFormat formatter = new SimpleDateFormat("HH:mm");
java.sql.Time StartTime = null;
try {
StartTime = new java.sql.Time(formatter.parse(time).getTime());
} catch (ParseException exception2) {
exception2.printStackTrace();
}
System.out.println("TIMEEEEEEEEEE====" + StartTime);

String time2 = "02:00";
java.sql.Time EndTime = null;
try {
EndTime = new java.sql.Time(formatter.parse(time2).getTime());
} catch (ParseException exception3) {
exception3.printStackTrace();
}
System.out.println("TIMEEEEEEEEEE====" + EndTime);


Timestamp timestamp1 = new Timestamp(StartDate.getYear(),
StartDate.getMonth(), StartDate.getDay(),
StartTime.getHours(), StartTime.getMinutes(), 00,
00);
Timestamp timestamp2 = new Timestamp(EndDate.getYear(),
EndDate.getMonth(), EndDate.getDay(),
EndTime.getHours(), EndTime.getMinutes(), 00, 00);

long milliseconds = timestamp2.getTime() - timestamp1.getTime();
int seconds = (int) milliseconds / 1000;

// calculate hours minutes and seconds
int hours = seconds / 3600;
int minutes = (seconds % 3600) / 60;
seconds = (seconds % 3600) % 60;
System.out.println(hours+"h:"+minutes+"m:"+"00s");



Test case


when I give date as 2010-01-05 and date2 as 2010-01-06 I am getting output as below

Date 2010-01-05
Date 2010-01-06
TIMEEEEEEEEEE====01:00:00
TIMEEEEEEEEEE====02:00:00
25h:0m:00s


when I give date as 2010-01-05 and date2 as 2010-01-11 I am getting output in negative value as below

Date 2010-01-05
Date 2010-01-11
TIMEEEEEEEEEE====01:00:00
TIMEEEEEEEEEE====02:00:00
-23h:0m:00s


Help me to correct if I am doing something wrong.
Thanks in advance.

Answer

The problem with your calculation is this: StartDate.getDay() etc.

getDay() will return the number of day of the week (read the JavaDoc) and not the day of the month. You'll need to use getDate() instead.

To illustrate the problem using your values: 2010-01-05 will return 2 for getDay() and thus you are getting 2010-01-02 as your timestamp. 2010-01-11 will return 1 for getDay() (it's 6 days later, i.e. (2 + 6) % 7 = 1) and hence your second timestamp becomes 2010-01-01. Now the second timestamp is before the first and hence you get a negative value.

However, as I already stated in my comments you should try and use some library or at least the non-deprecated built-in functionality for those calculations to save you a lot of headaches (I suggest you watch this video to get an idea of the challenges: https://youtube.com/watch?v=-5wpm-gesOY ).