Is it possible to suppress only Warn messages in Log4j2 while allowing all others

Question

I am using log4j2 to log messages in console and in a file. I am getting a lot of Warn message which I do not want. I only want to see Debug and other messages. is it possib

Answer 1

You can use the LevelRangeFilter to reject the log events.

Here's a simple class that generates some logs:

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class SomeClass {

    private static final Logger log = LogManager.getLogger();   

    public static void main(String[] args){

        if(log.isDebugEnabled())
            log.debug("This is some debug!");
        log.info("Here's some info!");
        log.warn("Warning will be rejected.");
        log.error("Some error happened!");
    }
}

Here's a basic configuration that just sends all events to console:

The output generated by the above is:

21:08:42.215 [main] DEBUG example.SomeClass - This is some debug!
21:08:42.217 [main] INFO  example.SomeClass - Here's some info!
21:08:42.217 [main] WARN  example.SomeClass - Warning will be rejected.
21:08:42.217 [main] ERROR example.SomeClass - Some error happened!

Now we add the LevelRangeFilter to the Console appender:

Now the output is:

21:15:26.987 [main] DEBUG example.SomeClass - This is some debug!
21:15:26.989 [main] INFO  example.SomeClass - Here's some info!
21:15:26.989 [main] ERROR example.SomeClass - Some error happened!

As you can see the WARN message is not logged to console.