单例，启动和log4j初始化：找不到记录器的附加程序

Question

We wrote a simple class like this:

import org.apache.log4j.Logger;
[...]
@Singleton
@Startup
public class ContactFormScheduler {

private static final Logger log = Logger.getLogger(ContactFormScheduler.class); 

[...]

When we start server (WildFly 10.1.0) we got the following error:

15:35:27,142 ERROR [stderr] (ServerService Thread Pool -- 58) log4j:WARN No appenders could be found for logger (com.test.ContactFormScheduler).

15:35:27,143 ERROR [stderr] (ServerService Thread Pool -- 58) log4j:WARN Please initialize the log4j system properly.

Any hints? What's the best way to initialize log4j?

In web.xml:

<context-param>
    <param-name>log4j-config-location</param-name>
    <param-value>/WEB-INF/log4j.properties</param-value> 
</context-param>

in jboss-deployment-structure.xml

<jboss-deployment-structure xmlns="urn:jboss:deployment-structure:1.2">
<deployment>
    <!-- Exclusions allow you to prevent the server from automatically adding some dependencies -->
    <exclusions>
        <module name="org.apache.log4j" />
    </exclusions>
</deployment>
</jboss-deployment-structure>

Others classes logs correctly.

Thanks Andrea

Answer 1

If you exclude log4j from being in your WAR/lib directory, remove the jboss-deployment-structure.xml and move the log4j.properties to WAR/WEB-INF/classes WildFly automatically configure log4j for your deployment.

If you'd rather use your own version of log4j you'd still need to move your log4j.properties to WAR/WEB-INF/classes directory as log4j wouldn't be able to read anything from the WAR/WEB-INF directory.