CODEWITHSUNDEEP
javadateparsingsimpledateformat
Supers1st
Supers1st

Reputation: 21

when hour = 12,it parses to 00, why?

When I'm going to get a long with new Date().getTime(), I find that when time > 11:59:59, it always resolve 00:xx:xx, for example; 12:00:00 --> 00:00:00, 12:23:56 --> 00:23:56;

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
Date parse = null;
try {
    parse = format.parse(str);
    log.debug("time{}", parse);
} catch (ParseException e) {
    e.printStackTrace();
}

when str = "2022-01-12 11:59:59" it works well;
when str = "2022-01-12 12:00:00" it works badly, it gives me 00:00:00;
when str = "2022-01-12 12:15:00" it works badly,it give me 00:15:00;
when str = "2022-01-12 13:15:00" it works well,it give me 13:00:00;

Upvotes: 2

Views: 1525

Answers (3)

Basil Bourque
Basil Bourque

Reputation: 339482

tl;dr

LocalDateTime.parse( "2022-01-12 12:15:00".replace( " " , "T" ) )

Details

As others said, your formatting pattern is incorrect in its use of hh for 12-hour clock rather than HH for 24-hour clock.

Furthermore, you are using terrible legacy date-time classes that were years ago supplanted by the modern java.time classes defined in JSR 310.

Your input strings nearly comply with the ISO 8601 standard for date-time strings. Replace the SPACE in the middle with a T.

String input = "2022-01-12 12:15:00".replace( " " , "T" ) ;

Parse as a LocalDateTime. No need to specify a formatting pattern.

LocalDateTime ldt = LocalDateTime.parse( input ) ;

Upvotes: 0

Tcheutchoua Steve
Tcheutchoua Steve

Reputation: 556

If you check the doc for SimpleDateFormat,

h == Hour in am/pm (1-12)

So 12pm is midnight.

If you want a 24hrs time, upper case 'H' rather than lower case 'h' to represent hour

H == Hour in day (0-23)

Upvotes: 3

Supers1st
Supers1st

Reputation: 21

i got it,it should be hh:mm:ss ---> HH:mm:ss

Upvotes: -1

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