1. Practice with “Hello world”
1.1 Add the dependency to your POM
<dependencies>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
1.2 Create your log4j.properties file into your resource folder
# Root logger option
log4j.rootLogger=ERROR, stdout
# syntax : log4j.logger.[my class Fully qualified name]=[log level], appender
log4j.logger.mypackage.Lelogger=ERROR, stdout
# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
1.3 Import log4J package into your class and Add a static object to your class
package mypackage;
import org.apache.log4j.Logger;
public class Lelogger {
static final Logger logger = Logger.getLogger(Leloggerbis.class.getName());
public static void main(String [ ] args)
{
logger.error("Hello World!");
}
}
2. Configuration
2.1 Additivity
In order to avoid logging multiple time due to the hierarchy of LoggerConfigs, you may set to false the “additivity” parameter of your logger
log4j.additivity.mypackage.Leloggerbis = false