k.logback-site.0.9.8.source-code.faq.html Maven / Gradle / Ivy
Logback FAQ
Logback Frequently Asked Questions
Logback Classic
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How can I use logback-classic with Jetty ?
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How does the automatic configuration work?
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How can I intercept JCL calls in Tomcat?
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How can I intercept JCL calls in Jetty ?
Logback Classic
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How can I use logback-classic with Jetty ?
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The Jetty application server uses SLF4J for its internal
logging. Here are the required steps to install logback
as SLF4J's underlaying implementation.
A few jars must be present in the
JETTY_HOME/lib
directory.
Logback-classic is based on the SLF4J api. Therefore,
the
slf4j-api-VERSION.jar
jar must be present. This jar can be downloaded from the
SLF4J
project.
Logback's own jars must also be present, namely
logback-core-VERSION.jar
and
logback-classic-VERSION.jar
.
To configure logback-classic, a file called
logback.xml
should be placed in the
JETTY_HOME/resources
directory. You can find configuration samples in the
examples/src/chapter4/conf/
directory, in the distribution of logback.
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How does the automatic configuration work?
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If a file called
logback.xml
is found in the classpath, then it is used.
In case it is not found, a
logback-test.xml
file is searched, and used if available.
If none of these files are available, logback uses its
BasicConfigurator
class to create a simple default configuration that will
only log to the console.
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How can I intercept JCL calls in Tomcat?
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When a dependency of your webapp logs using Jakarta
Commons Logging (for example Struts), you can intercept
these calls and redirect them to logback.
This can be done by using
jcl104-over-slf4j.jar
, a module that is shipped with
SLF4J
.
If you have only one webapp, its
WEB-INF/lib
directory should already contain the logback jars,
namely
logback-core-VERSION.jar
,
logback-classic-VERSION.jar
and
slf4j-api-VERSION.jar
. A logback configuration file, named
logback.xml
should be placed in the
WEB-INF/classes/
directory.
You now need to add
jcl104-over-slf4j.jar
to your
WEB-INF/lib
directory and remove
commons-logging-1.0.4.jar
. The logging that used to be directed to JCL should now
be handled by logback.
In case several webapps share the logback jars, you
might place the previously mentionned jars in the
common/lib/
directory of your Tomcat installation. The
logback.xml
file should then be placed in
common/classes
.
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How can I intercept JCL calls in Jetty ?
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Using logback as the logging implementation of choice
for frameworks depending on JCL can also be done in
Jetty.
In case you have only one webapp, the required steps are
exactly the same as
those needed in Tomcat
.
In case several webapps share the logback jars, you
might place the necessary jars in the
lib/
directory of your Jetty installation. The
logback.xml
file should then be placed in the
resources/
directory.
However, due to
Jetty's internal Classloading mechanism
, the
logback-classic-VERSION.jar
and
slf4j-api-VERSION.jar
files should also be placed in the
WEB-INF/lib/
directory of your webapps.
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