Log4j Change Level

Apache Logging Services Project - Apache log4j

import org.apache.log4j.Level;
import org.apache.log4j.Logger;
// ALL < DEBUG < INFO < WARN < ERROR < FATAL < OFF
public class Main {
 private static Logger log = Logger.getLogger(Main.class);

 public static void setLogLevel(Logger logger, String logLevel) {
  if (logLevel != null) {   
   logger.setLevel(Level.toLevel(logLevel));
   System.out.println("Change log4j Level: " + logLevel);
  }
 }
 
 private static void testLogLevel() {
  log.debug(new java.util.Date());
  log.info(new java.util.Date());
  log.warn(new java.util.Date());
  log.error(new java.util.Date());
  log.fatal(new java.util.Date());
 }
 
 public static void main(String[] args) throws Exception {
  setLogLevel(log, "ALL");
  testLogLevel();
  setLogLevel(log, "DEBUG");
  testLogLevel();
  setLogLevel(log, "INFO");
  testLogLevel();
  setLogLevel(log, "WARN");
  testLogLevel();
  setLogLevel(log, "ERROR");
  testLogLevel();  
  setLogLevel(log, "FATAL");
  testLogLevel();
  setLogLevel(log, "OFF");
  testLogLevel();
  setLogLevel(log, "ALL");
 } 
}
/*
Change log4j Level: ALL
[16:51:07 DEBUG Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 INFO  Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 WARN  Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 ERROR Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 FATAL Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
Change log4j Level: DEBUG
[16:51:07 DEBUG Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 INFO  Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 WARN  Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 ERROR Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 FATAL Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
Change log4j Level: INFO
[16:51:07 INFO  Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 WARN  Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 ERROR Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 FATAL Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
Change log4j Level: WARN
[16:51:07 WARN  Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 ERROR Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 FATAL Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
Change log4j Level: ERROR
[16:51:07 ERROR Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
[16:51:07 FATAL Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
Change log4j Level: FATAL
[16:51:07 FATAL Main:testLogLevel] Thu Mar 13 16:51:07 CST 2008
Change log4j Level: OFF
Change log4j Level: ALL
*/