Log4j2 auto config

2019-06-23 00:40发布

问题:

I have a problem applying the log4j2.xml auto configuration properly, and I think it has something to do with my folder arrangement.
I'm using maven to add log4j2 libs and arrange my projects as follows:
- one project to contain all "common" classes, used by server and client side of my system.
- another "core" project - the server side application.
Both projects use the same general package hierarchy (like com.foo.specific.package)

In the Common project I define a logger wrapper:

public class LogWrapper
{
    static Logger systemParentLogger = LogManager.getLogger("com.foo");

    public static Logger getLogger(Class<?> cls)
    {
        return LogManager.getLogger(cls.getName());
    }
}

Moreover, the Common project contains the log4j2.xml file under META-INF (alongside the persistence.xml file for Hibernate usage).

<?xml version="1.0" encoding="UTF-8"?>
<configuration name="PRODUCTION" status="OFF">

    <appenders>
        <appender type="RollingFile" 
            name="MyFileAppender" 
            fileName="logs/app.log" 
            filePattern="logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">
            <layout type="PatternLayout" pattern="%d %p %C{1.} [%t] %m%n"/>
        </appender>
    </appenders>

    <loggers>
        <root level="error">
            <appender-ref ref="MyFileAppender"/>
        </root>

        <logger name="com.foo" level="info" additivity="false">
            <appender-ref ref="MyFileAppender"/>
        </logger>

        <logger name="org.hibernate" level="error">
            <appender-ref ref=MyFileAppender"/>
        </logger>
    </loggers>

</configuration>

While running a sample code in the Core project (using the LogWrapper I wrote and some JPA voodoo), I could still see INFO hibernate logs, and no log file was created. I should state that while debugging the code, I could see that the logger fetched was given some weird value "com.foo.core.persistence.PersistenceXMLTest:ERROR in sun.misc.Launcher$AppClassLoader@2f600492"

回答1:

The log4j2.xml was placed in a "Folder" which in eclipse terms is "not on classpath".
Changing META-INF to be a "source folder" solved the problem.
In addition, the log4j2.xml file was not defined properly. These are the modifications needed:

<?xml version="1.0" encoding="UTF-8"?>
<configuration name="PRODUCTION" status="OFF">

<appenders>
    <RollingFile name="MyFileAppender" 
        fileName="../Logs/app.log" 
        filePattern="../Logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">
        <PatternLayout>
            <pattern>%d %p %C{1.} [%t] %m%n</pattern>
        </PatternLayout>
        <Policies>
            <OnStartupTriggeringPolicy />
            <TimeBasedTriggeringPolicy interval="6" modulate="true"/>
            <SizeBasedTriggeringPolicy size="250 MB"/>
        </Policies>
    </RollingFile>
</appenders>

<loggers>
    <root level="error">
        <appender-ref ref="MyFileAppender"/>
    </root>

    <logger name="com.foo" level="info" additivity="false">
        <appender-ref ref="MyFileAppender"/>
    </logger>
</loggers>

</configuration>

Still couldn't make the org.hibernate logger to be redirected to my logs, but at least I got the logger to work