How to customize log levels in logback?

1 year ago
Emily Johnson
2 minutes

To customize the log level, you can add a custom logger to the Logback configuration file and set its level.

To start with, define a custom logger in the configuration file of Logback (usually logback.xml).

<configuration>
  ...
  <logger name="com.example.custom" level="DEBUG" additivity="false">
    <appender-ref ref="STDOUT" />
  </logger>
  ...
</configuration>

In the configuration above, the “name” attribute of the “logger” element specifies the name of the custom logger, the “level” attribute specifies the log level (DEBUG), and the “additivity” attribute is used to control whether log events are passed to the ancestor logger (set to false here, indicating not to pass to other loggers).

Then, you can use a custom logger in the code, such as:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MyApp {
  private static final Logger logger = LoggerFactory.getLogger(MyApp.class);
  private static final Logger customLogger = LoggerFactory.getLogger("com.example.custom");
  
  public static void main(String[] args) {
    logger.debug("This is a debug message");
    customLogger.debug("This is a custom debug message");
  }
}

In the above code, obtain a custom logger by calling LoggerFactory.getLogger(“com.example.custom”) method, then use debug level methods to log.

In this way, the log level of the custom logger is set to DEBUG. Different levels can be set in the configuration file as needed.

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