仅在使用 log4j 时记录致命和错误消息

Question

I am new to log4j and trying to use log4j programmatically instead of using log4j.xml OR log4j.properties file.

But when I am running the code, It is only logging Fatal and Error messages and skipping other messages.

I have tried changing "rootlogger.setLevel(Level.DEBUG);" to "rootlogger.setLevel(Level.All);" but it is giving same output.

Could someone please help here?

import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.ConsoleAppender;

public class ProgrammaticLog4jExample {
    
    private static final Logger logger = Logger.getLogger(ProgrammaticLog4jExample.class);

    public static void main(String[] args) {
        // creates pattern layout
        String conversionPattern = "%-7p %d [%t] %c %x - %m%n";
        PatternLayout layout = new PatternLayout(conversionPattern);
        
        // creates console appender
        ConsoleAppender consoleAppender = new ConsoleAppender();
        consoleAppender.setLayout(layout);
        consoleAppender.activateOptions();
        
        // configure the root logger
        Logger rootlogger = Logger.getRootLogger();
        rootlogger.setLevel(Level.DEBUG);
        rootlogger.addAppender(consoleAppender);
                
        
        // creates a custom logger and messages
        logger.debug("this is a debug log message");
        logger.info("this is a information message");
        logger.warn("this is a warning message");
        logger.fatal("this is the fatal message");
        logger.error("This is the error message");
    }
}

output:

19:07:58.003 [main] FATAL log4jExample.ProgrammaticLog4jExample - this is the fatal message

19:07:58.006 [main] ERROR log4jExample.ProgrammaticLog4jExample - This is the error message

output Image:

I am using below jar files for log4j in my project classpath:

Answer 1

Aha...After doing some more experiments, I have got the answer.

Added "logger.setLevel(Level.DEBUG);" and I am able to get all the logs now. :-)

import org.apache.log4j.ConsoleAppender;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;

   
public class ProgrammaticLog4jExample {
    
    private static final Logger logger = Logger.getLogger(ProgrammaticLog4jExample.class);

    public static void main(String[] args) {
        // creates pattern layout
        String conversionPattern = "%-7p %d [%t] %c %x - %m%n";
        PatternLayout layout = new PatternLayout(conversionPattern);
        
        // creates console appender
        ConsoleAppender consoleAppender = new ConsoleAppender();
        consoleAppender.setLayout(layout);
        consoleAppender.activateOptions();
        
        // configure the root logger
        Logger rootlogger = Logger.getRootLogger();
        rootlogger.setLevel(Level.DEBUG);
        rootlogger.addAppender(consoleAppender);
                
        logger.setLevel(Level.DEBUG);
        // creates a custom logger and messages
        // Logger logger = Logger.getLogger(ProgrammaticLog4jExample.class.getName());
        logger.debug("this is a debug log message");
        logger.info("this is a information message");
        logger.warn("this is a warning message");
        logger.fatal("this is the fatal message");
        logger.error("This is the error message");
    }
}

Output Image: