Log4j is an open source project developed and maintained by Apache. It is part of a bigger open source project known as the Apache Logging Services.
The following code sample shows how to use Log4j in its basic configuration.
package il.ac.hit.samples; import org.apache.log4j.BasicConfigurator; import org.apache.log4j.Logger; public class SimpleLoop { static Logger logger = Logger.getLogger("SimpleLoop"); public static void main(String args[]) { BasicConfigurator.configure(); for (int i = 0; i <= 10; i++) { System.out.println("i=" + i); logger.info("i equals " + i); } } }
The following video clips shows the execution of this code sample and explains it.
The following code sample shows how we can add a FileAppender to the logger we use.
package il.ac.hit.samples; import java.io.IOException; import org.apache.log4j.BasicConfigurator; import org.apache.log4j.FileAppender; import org.apache.log4j.Logger; import org.apache.log4j.SimpleLayout; public class SimpleLoopFileAppender { static Logger logger = Logger.getLogger("SimpleLoop"); public static void main(String args[]) { BasicConfigurator.configure(); try { logger.addAppender(new FileAppender(new SimpleLayout(), "logs.txt")); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } for (int i = 0; i <= 10; i++) { System.out.println("i=" + i); logger.info("i equals " + i); } } }
The following video clip shows and explains the execution of this code.