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DateFormat(3pm) User Contributed Perl Documentation DateFormat(3pm)
NAME
Log::Log4perl::DateFormat - Log4perl advanced date formatter helper class
SYNOPSIS
# Either in a log4j.conf file ...
log4perl.appender.Logfile.layout = \
Log::Log4perl::Layout::PatternLayout
log4perl.appender.Logfile.layout.ConversionPattern = %d{MM/dd HH:mm} %m
# ... or via the PatternLayout class ...
use Log::Log4perl::Layout::PatternLayout;
my $layout = Log::Log4perl::Layout::PatternLayout->new(
"%d{HH:mm:ss,SSS} %m");
# ... or even directly with this helper class:
use Log::Log4perl::DateFormat;
my $format = Log::Log4perl::DateFormat->new("HH:mm:ss,SSS");
my $time = time();
print $format->format($time), "\n";
# => "17:02:39,000"
DESCRIPTION
"Log::Log4perl::DateFormat" is a helper class for the advanced date formatting functions
in "Log::Log4perl::Layout::PatternLayout", and adheres (mostly) to the log4j
SimpleDateFormat spec available on
http://download.oracle.com/javase/1.4.2/docs/api/java/text/SimpleDateFormat.html
It supports the following placeholders:
Symbol Meaning Presentation Example
------ ------- ------------ -------
G era designator (Text) AD
e epoch seconds (Number) 1315011604
y year (Number) 1996
M month in year (Text & Number) July & 07
d day in month (Number) 10
h hour in am/pm (1~12) (Number) 12
H hour in day (0~23) (Number) 0
m minute in hour (Number) 30
s second in minute (Number) 55
S millisecond (Number) 978
E day in week (Text) Tuesday
D day in year (Number) 189
F day of week in month (Number) 2 (2nd Wed in July)
w week in year (Number) 27
W week in month (Number) 2
a am/pm marker (Text) PM
k hour in day (1~24) (Number) 24
K hour in am/pm (0~11) (Number) 0
z time zone (Text) Pacific Standard Time
Z RFC 822 time zone (Text) -0800
' escape for text (Delimiter)
'' single quote (Literal) '
Presentation explanation:
(Text): 4 or more pattern letters--use full form, < 4--use short or
abbreviated form if one exists.
(Number): the minimum number of digits. Shorter numbers are
zero-padded to this amount. Year is handled
specially; that is, if the count of 'y' is 2, the
Year will be truncated to 2 digits.
(Text & Number): 3 or over, use text, otherwise use number.
For example, if you want to format the current Unix time in "MM/dd HH:mm" format, all you
have to do is specify it in the %d{...} section of the PatternLayout in a Log4perl
configuration file:
# log4j.conf
# ...
log4perl.appender.Logfile.layout = \
Log::Log4perl::Layout::PatternLayout
log4perl.appender.Logfile.layout.ConversionPattern = %d{MM/dd HH:mm} %m
Same goes for Perl code defining a PatternLayout for Log4perl:
use Log::Log4perl::Layout::PatternLayout;
my $layout = Log::Log4perl::Layout::PatternLayout->new(
"%d{MM/dd HH:mm} %m");
Or, on a lower level, you can use the class directly:
use Log::Log4perl::DateFormat;
my $format = Log::Log4perl::DateFormat->new("MM/dd HH:mm");
my $time = time();
print $format->format($time), "\n";
While the "new()" method is expensive, because it parses the format strings and sets up
all kinds of structures behind the scenes, followup calls to "format()" are fast, because
"DateFormat" will just call "localtime()" and "sprintf()" once to return the formatted
date/time string.
So, typically, you would initialize the formatter once and then reuse it over and over
again to display all kinds of time values.
Also, for your convenience, the following predefined formats are available, just as
outlined in the log4j spec:
Format Equivalent Example
ABSOLUTE "HH:mm:ss,SSS" "15:49:37,459"
DATE "dd MMM yyyy HH:mm:ss,SSS" "06 Nov 1994 15:49:37,459"
ISO8601 "yyyy-MM-dd HH:mm:ss,SSS" "1999-11-27 15:49:37,459"
APACHE "[EEE MMM dd HH:mm:ss yyyy]" "[Wed Mar 16 15:49:37 2005]"
So, instead of passing
Log::Log4perl::DateFormat->new("HH:mm:ss,SSS");
you could just as well say
Log::Log4perl::DateFormat->new("ABSOLUTE");
and get the same result later on.
Known Shortcomings
The following placeholders are currently not recognized, unless someone (and that could be
you :) implements them:
F day of week in month
w week in year
W week in month
k hour in day
K hour in am/pm
z timezone (but we got 'Z' for the numeric time zone value)
Also, "Log::Log4perl::DateFormat" just knows about English week and month names,
internationalization support has to be added.
Millisecond Times
More granular timestamps down to the millisecond are also supported, just provide the
millsecond count as a second argument:
# Advanced time, resoluion in milliseconds
use Time::HiRes;
my ($secs, $msecs) = Time::HiRes::gettimeofday();
print $format->format($secs, $msecs), "\n";
# => "17:02:39,959"
LICENSE
Copyright 2002-2016 by Mike Schilli <m AT perlmeister.com> and Kevin Goess <cpan AT goess.org>.
This library is free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
AUTHOR
Please contribute patches to the project on Github:
http://github.com/mschilli/log4perl
Send bug reports or requests for enhancements to the authors via our
MAILING LIST (questions, bug reports, suggestions/patches):
log4perl-devel AT lists.net
Authors (please contact them via the list above, not directly): Mike Schilli
<m AT perlmeister.com>, Kevin Goess <cpan AT goess.org>
Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy
Bopp, Hutton Davidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, Anthony Foiani, James
FitzGibbon, Carl Franks, Dennis Gregorovic, Andy Grundman, Paul Harrington, Alexander
Hartmaier David Hull, Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter, Brett
Rann, Peter Rabbitson, Erik Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac
Yang.
perl v5.32.1 2021-02-14 DateFormat(3pm)
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