Configuration files

 

Configuration files

Why we have used Log4J? "It's highly configurable"? No - all is hard coded! But that is not the debt of Log4J - it's ours. We had coded BasicConfigurator.configure(); which implies a simple, but hard coded configuration. More confortable would be using a property file. In the java source delete the BasicConfiguration-line from the main() method (and the related import-statement). Log4J will search then for a configuration as described in it's manual. Then create a new file src/log4j.properties. That's the default name for Log4J's configuration and using that name would make life easier - not only the framework knows what is inside, you too!

log4j.rootLogger=DEBUG, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender

log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

log4j.appender.stdout.layout.ConversionPattern=%m%n

This configuration creates an output channel ("Appender") to console named as stdout which prints the message (%m) followed by a line feed (%n) - same as the earlier System.out.println() :-) Oooh kay - but we haven't finished yet. We should deliver the configuration file, too. So we change the buildfile:

    ...

<target name="compile">

<mkdir dir="${classes.dir}"/>

<javac srcdir="src" destdir="${classes.dir}" classpathref="classpath"/>

<copy todir="${classes.dir}">

<fileset dir="src" excludes="**/*.java"/>

</copy>

</target>

...

This copies all resources (as long as they haven't the suffix ".java") to the build directory, so we could start the application from that directory and these files will included into the jar.