CODEWITHSUNDEEP
javadatetime
Space Rocker
Space Rocker

Reputation: 787

How to calculate the time difference between two events in Java?

I want to calculate time difference in seconds between to time instants. For example, during execution of the program, I set the value of a variable and after some time I change it again. What was the time difference between the recent change of value from the previous value?

Upvotes: 10

Views: 14296

Answers (4)

yurib
yurib

Reputation: 8147

You can use System.currentTimeMillis() to save the current time at one millisecond resolution. Just save the time whenever the first event occurs (better use a long var to hold that value) and again when the 2nd event occurs. The difference divided by 1000 will give you time difference in seconds.

Upvotes: 14

Thorbjørn Ravn Andersen
Thorbjørn Ravn Andersen

Reputation: 75356

Store the current time when you need to as retrieved from System.nanoTime(), and subtract any two of these values to get the difference in nanoseconds.

(By integer division first by a million and then float by a thousand you get a time in seconds with three decimal places, which prints nicely.)

Upvotes: 3

Roman
Roman

Reputation: 66156

You can do something as simple as this:

long begin = System.currentTimeMillis();
doWork();
long end = System.currentTimeMillis();

long dt = end - begin;

More mature way (especially, if you need to do it many time in many places) is using a library. Look at perf4j. You can put @Profiled annotation on methods and it will automatically generate some statistics and write it to a log file.

Upvotes: 5

zellio
zellio

Reputation: 32484

Just fetch it from the system and store in long data. You can do math on those longs to figure out the time differential.

long start = System.currentTimeMillis();

//do stuff
//do more stuff

long end = System.currentTimeMillis();

Upvotes: 1

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