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Configuring and Writing Logs

To write strict logging entries directly from a Spring Class, you instantiate a generic internal Logger.

Writing Logs in Java​

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;

@Service
public class UserService {
    
    // Instantiate the SLF4J logger targeting the class name securely
    private static final Logger logger = LoggerFactory.getLogger(UserService.class);

    public void processUser(String username) {
        logger.info("Initializing processing for user: {}", username);
        
        try {
            // Processing logic
        } catch (Exception e) {
            logger.error("Severe failure occurred processing user", e);
        }
    }
}

Note: If you use the Project Lombok dependency, you can simply place @Slf4j above the class definition, and Lombok automatically injects the log variable instance internally.

Modifying Spring Properties​

You can dictate global logging configuration utilizing src/main/resources/application.properties.

To enforce DEBUG logs exclusively for your com.codenbuild package while ignoring generic framework debug spam:

logging.level.com.codenbuild=DEBUG
logging.level.org.springframework=WARN

Logging to a File​

By default, Spring completely restricts logging strictly to the Console view. To generate physical logs required for external monitoring platforms (like Splunk or Datadog), you define an output configuration natively.

# System file configuration
logging.file.name=logs/codenbuild.log
logging.logback.rollingpolicy.max-file-size=10MB
logging.logback.rollingpolicy.max-history=30

This forces Spring to dump output logs continuously targeting logs/codenbuild.log, archiving them daily or whenever the file breaches the 10MB data limit.