How can I perform arithmetic operation with dates in Java? [duplicate]

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How开发者_Python百科 to calculate time difference in java?

Actually I want to subtract two dates in Java. I tried a lot but can't succeed. So anyone please help me.

Date dtStartDate=pCycMan.getStartDate();

Date dtEndDate=pCycMan.getEndDate();

How can I subtract these two Dates?

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long msDiff = dtEndDate.getTime() - dtStartDate.getTime()

msDiff now holds the number of milliseconds difference between the two dates. Feel free to use the division and mod operators to convert to other units.

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how can i subtract these two Dates?

You can get the difference in milliseconds like this:

dtEndDate.getTime() - dtStartDate.getTime()

(getTime returns the number of milliseconds since January 1, 1970, 00:00:00 GMT.)

However, for this type of date arithmetics the Joda time library, which has proper classes for time durations (Duration) is probably a better option.

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To substract to dates you can get them both as longs getTime() and subtract the values that are returned.

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Create two Calendar objects from those Dates and then use the add() method (which can be used to subtrade dates too).

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There is a framework to work with the date in java... http://joda-time.sourceforge.net/userguide.html take a look, i'm sure that it can help you

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long diffInMillis = dtEndDate.getTimeInMillis() -  dtStartDate.getTimeInMillis();

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It depends what do you want. To get difference in milliseconds say dtStartDate.getTime() - dtEndDate.getTime().

To get difference in days, hours etc use Calendar class (methods like after, before, compareTo, roll may help).

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Use the Calendar class.

Usage:

Calendar c = Calendar.getInstance();
c.setTime(dtStartDate);
int date = c.get(Calendar.YEAR); //int represents the year of the date
int dayOfWeek = c.get(Calendar.DAY_OF_WEEK); // int represents dayOfWeek as defined in link.