ejb and web app. logging with log4j

[Yan Zhou]

Hi,

Since EJB standards discourage using file i/o, how do people use log4j in EJBs to log to text files? I would like to use text file logging because alternatives such as logging to JMS or DB might be too expensive for loggin. For instance, how to load log4j.properties, where is the logging file physically located, how would that affect my EJBs?

What about J2EE Web app, why the same restriction on EJB does not apply on web app.? Again, if I use log4j in servlet, how do I load log4j.properties, and where is the logging file physically located?

Thanks.
Yan

[Bruno Collet]

You should read Log4J tutorial.
A few beginning of answers:
- EJBs cannot directly access the file system because of their distributed nature.
- You do not need to explicitly load the log4j properties file. The log4j component does it for you. In this file you can configure appenders. Obviously you only need a FileAppender (i.e. an ordinary log file).

In case you use JBoss I have a small document showing a basic log4j config for JBoss on my website.

[Praveena Venigalla]

Hi,
As EJB's cannot directly acess the file system:
one solution for logging to text file from EJB is write some Helper(Java) class.
First put the log4j.properties file in one location like C://log4j/log4j.properties.
In log4j.properties you have to mention where the log file has to be created.
In helper class:
Logger logger=Logger.getLogger("some string val");
PropertyConfigurator.configure("/log4j/log4j.properties");--this will read the log4j.properties file.
write a method which creats Logger object and return the logger to calling method.
In your EJB call this method and get the logger.
From this logger you can write debug or error or warn statements.
You can use the same class from servlet also.

Let me know if u have any Questions.

Praveena.
[ December 08, 2004: Message edited by: Praveena Venigalla ]

[Seetesh Hindlekar]

Hi Praveena,

PropertyConfigurator.configure("/log4j/log4j.properties");--this will read the log4j.properties file.

Where is the log4j.properties file expected to be placed?

We did keep this file in the classes folder of Weblogic 8.1 Server but we get a message that the Resource file not found. The classpath in Environment variables setting has the name of the folder "classes".

Rgds,

Seetesh