如何将两个不同的字符串转换为日期格式并在JSP / JAVA中找到它们的差异

Question

I have 2 strings Str1: 2016-7-25.15.38. 32. 0 (This is what im getting from DB) String2 : July 25, 2016 3:19 PM (This one I wrote a program to read from the email timestamp)

How to convert these 2 strings to date format and find their differnce in time.. Pls help. Ive gone through so many pages in SO and google but not getting anything specific

Answer 1

How to convert these 2 strings to date format

Using Java 8, you'd parse them like this:

ZoneId zoneId = ZoneId.systemDefault();
ZonedDateTime dt1 = ZonedDateTime.parse("2016-7-25.15.38. 32. 0",
            DateTimeFormatter.ofPattern("uuuu-M-d.H.m. s. 0").withZone(zoneId));
ZonedDateTime dt2 = ZonedDateTime.parse("July 25, 2016 3:19 PM",
            DateTimeFormatter.ofPattern("MMMM d, uuuu h:mm a").withZone(zoneId));

^{Using a non-standard indentation to align format string with value to be parsed, for easier comparison.}

The code is using ZonedDateTime so Daylight Savings Time will be handled correctly.

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and find their difference in time

Getting the difference in time is then easy enough, using until() or between() :

long seconds = dt1.until(dt2, ChronoUnit.SECONDS);
long seconds = ChronoUnit.SECONDS.between(dt1, dt2);

They are the same. Use whichever you like best.

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If you print the values above, you get (I'm in USA Eastern time zone):

2016-07-25T15:38:32-04:00[America/New_York]
2016-07-25T15:19-04:00[America/New_York]
-1172

Answer 2

I would simply use Oracle to figure out the difference. It's quite easy:

select to_date('2016-07-25.15.38.32', 'yyyy-mm-dd.hh24.mi.ss') - to_date('July 25, 2016 3:19 PM', 'Month dd, yyyy hh:mi PM') from dual

Answer 3

First you need to parse those two strings into Date objects. You can use SimpleDateFormat class for parsing. Once you have two Data objects, you can easily get the date difference.

Answer 4

1. Convert java.sql.timestamp into java.util.Date

Date startDate = new Date(startTimestamp.getTime());
Date endDate= new Date(endTimestamp.getTime());

2.You can find the time difference using TimeUnit enum as below.

Date startDate = // Set start date
Date endDate   = // Set end date

long duration  = endDate.getTime() - startDate.getTime();

long diffInSeconds = TimeUnit.MILLISECONDS.toSeconds(duration);
long diffInMinutes = TimeUnit.MILLISECONDS.toMinutes(duration);
long diffInHours = TimeUnit.MILLISECONDS.toHours(duration);

and so on..