1. Have log4j jar file to place into:
2. Have property file to place into :
3 .Example property file will :
log4j.rootLogger=WARN, Other log4j.appender.Other=org.apache.log4j.RollingFileAppender log4j.appender.Other.File=D:/Work/web/WEB-INF/logs/root.log log4j.appender.Other.MaxFileSize=1000KB log4j.appender.Other.MaxBackupIndex=3 log4j.appender.Other.layout=org.apache.log4j.PatternLayout log4j.appender.Other.layout.ConversionPattern=%d [%t] %-5p %c - %m%n log4j.logger.my.com.leadingside=DEBUG, appLog log4j.additivity.my.com.leadingside=false log4j.appender.appLog=org.apache.log4j.RollingFileAppender log4j.appender.appLog.File=D:/Work/web/WEB-INF/logs/app.log log4j.appender.appLog.MaxFileSize=1000KB log4j.appender.appLog.MaxBackupIndex=3 log4j.appender.appLog.layout=org.apache.log4j.PatternLayout log4j.appender.appLog.layout.ConversionPattern=%d %-5p %c - %m%n
4. Copy below code for testing
import org.apache.log4j.Level; import org.apache.log4j.Logger; public class TestLogger{ static Logger myLogger = Logger.getLogger(TestLogger.class.getName( )); public static void main(String [] args){ myLogger.setLevel(Level.DEBUG); myLogger.warn("SUccess Debug From LOGER"); } }
5. NOTE / Attention !!
DEBUG, INFO, WARN, ERROR, FATAL
following sequense, debug is the lowest level, means, it will log for
INFO, WARN, ERROR, FATAL
BUT if we set level to WARN, logger will log only ERROR, FATAL.
eg: myLogger.setLevel(Level.ERROR);
myLogger.warn(“SUccess Debug From LOGER”);