Read configuration from a file.
The existing configuration is
not cleared nor reset. If you require a different behavior,
then call
resetConfiguration
method before calling
doConfigure
.
The configuration file consists of statements in the format
key=value
. The syntax of different configuration
elements are discussed below.
Repository-wide threshold
The repository-wide threshold filters logging requests by level
regardless of logger. The syntax is:
log4j.threshold=[level]
The level value can consist of the string values OFF, FATAL,
ERROR, WARN, INFO, DEBUG, ALL or a
custom level value. A
custom level value can be specified in the form
level#classname. By default the repository-wide threshold is set
to the lowest possible value, namely the level
ALL
.
Appender configuration
Appender configuration syntax is:
# For appender named appenderName, set its class.
# Note: The appender name can contain dots.
log4j.appender.appenderName=fully.qualified.name.of.appender.class
# Set appender specific options.
log4j.appender.appenderName.option1=value1
...
log4j.appender.appenderName.optionN=valueN
For each named appender you can configure its
Layout
. The
syntax for configuring an appender's layout is:
log4j.appender.appenderName.layout=fully.qualified.name.of.layout.class
log4j.appender.appenderName.layout.option1=value1
....
log4j.appender.appenderName.layout.optionN=valueN
Configuring loggers
The syntax for configuring the root logger is:
log4j.rootLogger=[level], appenderName, appenderName, ...
This syntax means that an optional
level can be
supplied followed by appender names separated by commas.
The level value can consist of the string values OFF, FATAL,
ERROR, WARN, INFO, DEBUG, ALL or a
custom level value. A
custom level value can be specified in the form
level#classname
.
If a level value is specified, then the root level is set
to the corresponding level. If no level value is specified,
then the root level remains untouched.
The root logger can be assigned multiple appenders.
Each
appenderName (separated by commas) will be added to
the root logger. The named appender is defined using the
appender syntax defined above.
For non-root categories the syntax is almost the same:
log4j.logger.logger_name=[level|INHERITED|NULL], appenderName, appenderName, ...
The meaning of the optional level value is discussed above
in relation to the root logger. In addition however, the value
INHERITED can be specified meaning that the named logger should
inherit its level from the logger hierarchy.
If no level value is supplied, then the level of the
named logger remains untouched.
By default categories inherit their level from the
hierarchy. However, if you set the level of a logger and later
decide that that logger should inherit its level, then you should
specify INHERITED as the value for the level value. NULL is a
synonym for INHERITED.
Similar to the root logger syntax, each
appenderName
(separated by commas) will be attached to the named logger.
See the
appender
additivity rule in the user manual for the meaning of the
additivity
flag.
ObjectRenderers
You can customize the way message objects of a given type are
converted to String before being logged. This is done by
specifying an
ObjectRenderer
for the object type would like to customize.
The syntax is:
log4j.renderer.fully.qualified.name.of.rendered.class=fully.qualified.name.of.rendering.class
As in,
log4j.renderer.my.Fruit=my.FruitRenderer
Logger Factories
The usage of custom logger factories is discouraged and no longer
documented.
Example
An example configuration is given below. Other configuration
file examples are given in the
examples
folder.
# Set options for appender named "A1".
# Appender "A1" will be a SyslogAppender
log4j.appender.A1=org.apache.log4j.net.SyslogAppender
# The syslog daemon resides on www.abc.net
log4j.appender.A1.SyslogHost=www.abc.net
# A1's layout is a PatternLayout, using the conversion pattern
# %r %-5p %c{2} %M.%L %x - %m\n. Thus, the log output will
# include # the relative time since the start of the application in
# milliseconds, followed by the level of the log request,
# followed by the two rightmost components of the logger name,
# followed by the callers method name, followed by the line number,
# the nested disgnostic context and finally the message itself.
# Refer to the documentation of PatternLayout
for further information
# on the syntax of the ConversionPattern key.
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-4r %-5p %c{2} %M.%L %x - %m\n
# Set options for appender named "A2"
# A2 should be a RollingFileAppender, with maximum file size of 10 MB
# using at most one backup file. A2's layout is TTCC, using the
# ISO8061 date format with context printing enabled.
log4j.appender.A2=org.apache.log4j.RollingFileAppender
log4j.appender.A2.MaxFileSize=10MB
log4j.appender.A2.MaxBackupIndex=1
log4j.appender.A2.layout=org.apache.log4j.TTCCLayout
log4j.appender.A2.layout.ContextPrinting=enabled
log4j.appender.A2.layout.DateFormat=ISO8601
# Root logger set to DEBUG using the A2 appender defined above.
log4j.rootLogger=DEBUG, A2
# Logger definitions:
# The SECURITY logger inherits is level from root. However, it's output
# will go to A1 appender defined above. It's additivity is non-cumulative.
log4j.logger.SECURITY=INHERIT, A1
log4j.additivity.SECURITY=false
# Only warnings or above will be logged for the logger "SECURITY.access".
# Output will go to A1.
log4j.logger.SECURITY.access=WARN
# The logger "class.of.the.day" inherits its level from the
# logger hierarchy. Output will go to the appender's of the root
# logger, A2 in this case.
log4j.logger.class.of.the.day=INHERIT
Refer to the
setOption method in each Appender and
Layout for class specific options.
Use the
#
or
!
characters at the
beginning of a line for comments.