DZone Snippets: log4j code

Java: log4j Initialization Example

thitiv (Thiti V. Sintopchai) — Mon, 14 May 2007 09:44:45 GMT

// Initialization for Basic Console Output
// Ref: http://logging.apache.org/log4j/docs/manual.html



 import com.foo.Bar;



 // Import log4j classes.

 import org.apache.log4j.Logger;

 import org.apache.log4j.BasicConfigurator;



 public class MyApp {



   // Define a static logger variable so that it references the

   // Logger instance named "MyApp".

   static Logger logger = Logger.getLogger(MyApp.class);



   public static void main(String[] args) {



     // Set up a simple configuration that logs on the console.

     BasicConfigurator.configure();



     logger.setLevel(Level.DEBUG); // optional if log4j.properties file not used

     // Possible levels: TRACE, DEBUG, INFO, WARN, ERROR, and FATAL



     logger.info("Entering application.");

     Bar bar = new Bar();

     bar.doIt();

     logger.info("Exiting application.");

   }

 }

Log4j 101

JohnMunsch (John Munsch) — Mon, 23 Apr 2007 14:43:26 GMT

// Once you have included the Log4j jar into the classpath of your
// application, you can use the following code within each class to
// get a logger for that class. That is, all log messages issued from
// within that class will be tagged with the classname to make it
// easier to locate a problem. See my tutorial on Log4j,
// Log4j in 30 Minutes or Less (http://www.johnmunsch.com/projects/Presentations/)
// for a better introduction.



private static Logger log = Logger.getLogger(.class);

// When you need to specify the location (or a different name) for
// the log.properties file, you can set a specific System variable
// which Log4j will be guaranteed to read as soon as any part of
// your code tries to use it. You do that by passing the following
// to the JVM as you start your Java application.



-Dlog4j.configuration=file:

Configure log4j to log info level to xml file

vincente (vincente) — Wed, 07 Feb 2007 06:20:25 GMT

log4j.properties: eclipse log4j HOWTO in 10 minutes

dgasull (Daniel González Gasull) — Fri, 05 Jan 2007 16:28:34 GMT

// How to use log4j within eclipse in 10 minutes



# HOW TO USE LOG4J WITHIN ECLIPSE IN 10 MINUTES

# by Daniel Gonzalez Gasull  gasull[at]gmail[dot]com

#

# 1) Download log4j http://logging.apache.org/site/binindex.cgi

# 2) Unpack the .zip file in your Java folder (In Windows it is usually 

# C:\Program Files\Java\)

# 3) In Eclipse: Window - Preferences... - Java - Build Path - User Libraries - 

# New - write "log4j" - OK - Add JARs... - navigate to find your log4j .jar you just

# unpacked in the Java Folder - OK 

# 4) right click on your project in the Package Explorer - New - Folder - 

# in "Folder name" write "log4j" - click Advanced - select "Link to a folder in the

# file system" - create a new folder "log4j" in your project folder in the file system

# 5) Place this file you are reading right now in in the folder you just created.  Name

# the file as log4j.properties

# 6) In Eclipse: Run - Run... - In the navigation bar on the left select either the 

# server, or the runnable class, or the JUnit test you want to log with log4j -

# select the Classpath tab - User Entries - Advanced... - Add folders - OK - select 

# the "log4j" folder you created in your project - OK   

# 7) Repeat step 6 for other servers, runnable classes or JUnit tests you want to log

# 8) Change in the following line the "org.example.foo.bar" with whatever you want.

log4j.category.org.example.foo.bar=DEBUG

# 9) Add the following import to the Java Class you want to log:

#	import org.apache.log4j.Logger;

# 10) Add this lines to the Java Class you want to log:

#	/**

#	 * Log4j logger

#	 */

#	static Logger log4j = Logger.getLogger("org.example.foo.bar");

# 11) Substitute in the code above "org.example.foo.bar" with whatever your wrote in

# in the step 8.

# 12) Add something like the following code in your Class whenever you want to log:

#	log4j.debug("WTF?");

# 13) Repeat steps 9, 10, 11 and 12 for every Java Class you want to log

# 14) Enjoy!





log4j.rootCategory=DEBUG, R, O



# Stdout

log4j.appender.O=org.apache.log4j.ConsoleAppender



# File

log4j.appender.R=org.apache.log4j.RollingFileAppender

log4j.appender.R.File=log4j.log



# Control the maximum log file size

log4j.appender.R.MaxFileSize=100KB



# Archive log files (one backup file here)

log4j.appender.R.MaxBackupIndex=1



log4j.appender.R.layout=org.apache.log4j.PatternLayout

log4j.appender.O.layout=org.apache.log4j.PatternLayout



log4j.appender.R.layout.ConversionPattern=[%d{ISO8601}]%5p%6.6r[%t]%x - %C.%M(%F:%L) - %m%n

log4j.appender.O.layout.ConversionPattern=[%d{ISO8601}]%5p%6.6r[%t]%x - %C.%M(%F:%L) - %m%n



Configure Log4J in a WebObjects app
rentzsch (Jonathan 'Wolf' Rentzsch) — Thu, 14 Apr 2005 04:06:06 GMT
(new DOMConfigurator()).doConfigure(resourceManager().inputStreamForResourceNamed("log4j.xml", "app", null), LogManager.getLoggerRepository());