log4j is one of the most powerful and commonly used logging system used when programming in Java. There are many different ways how you can utilize it in your project. One of the features of log4j framework is to store Java log messages to a JDBC-enabled database. Here we will show how to store the logs into CUBRID Database. Since CUBRID provides the JDBC interface, configuration log4j is pretty straightforward.

Downloads

• CUBRID 1.1 or higher
  Download the latest version of CUBRID Database, and follow the installation instructions.
• Java Development Kit
  Download the latest JDK from http://www.oracle.com/technetwork/java/javase/downloads/index.html.
• log4j
  Download log4j from http://logging.apache.org/log4j/1.2/download.html.

Example

Before we get into configurations, let's create a sample code in Java.

• Create a new directory where for this example.
• Copy two libraries to this directory:
1. log4j-1.2.16.jar ? This is the main log4j library. You can find it inside the log4j archive you have downloaded above.
2. cubrid_jdbc.jar ? This is the main CUBRID JDBC driver. You can find it in the /jdbc directory which is located inside the main directory where you have installed CUBRID.
• Now let's create a simple Java class that does some logging. Open your editor and create a new file called Tutorial.java.
import org.apache.log4j.Logger; import org.apache.log4j.LogManager; public class Tutorial { public static void main( String[] args ) { Logger log = LogManager.getLogger(Tutorial.class); log.info("Application successfully initialized"); log.warn("Application is about to finish"); try { if ( 1 / 0 == 0 ) { System.out.println("Fry the FPU"); } } catch( Exception ex) { log.error("Some exception has been thrown", ex); } log.fatal("Application has finished"); } }

Configure log4j

In order to enable log4j we will have to create a configuration file. In this configuration we will define three appenders: Console, File and JDBC. This way, the messages will be written to all these appenders. Open text editor and put the following configuration (note that CUBRID JDBC specific code is written in bold). Save as log4j.properties in the same directory with Java file.

As you can see, configuring the JDBC appender requires specifying JDBC URL and also the connection credentials. Additionally we have set the format of the timestamp into log4j.appender.CUBRID.sql in order to create a database compatible DATETIME value.

Next, before we can use the JDBC logging with CUBRID we will have to create a new table to store the logs. By default, CUBRID comes with a sample database named demodb accessible to dba user with an empty password. We will use this database to store our table for logging. Open up the command line terminal and execute the following SQL statement using csql utility to create our table. You can, in fact, achieve the same results if you use the CUBRID Manager, CUBRID's main GUI-based database administration tool.

Now compile your Java source code into Java .class with the following command. This will output the Tutorial.class file.

Then run the Tutorial.class.

You will see the following output.

Let's look into our CUBRID Database Table. With csql utility select all records from our table.

You will see the following results.

Setting up log4j with CUBRID is very simple and straightforward as you can see. However, log4j by itself has one drawback - it does not log Java exceptions into the JDBC appender. If you navigate to log4j website, it states: "WARNING: This version of JDBCAppender is very likely to be completely replaced in the future. Moreoever, it does not log exceptions." So, we recommend you to consult the documentation before you decide to use the JDBC appender with any database.

See also

• log4j home page http://logging.apache.org/log4j/1.2/
• log4jdbc home page http://code.google.com/p/log4jdbc/
• SLF4J manual http://www.slf4j.org/manual.html
• log4j manual http://logging.apache.org/log4j/1.2/manual.html
• THE COMPLETE LOG4J MANUAL - Google Books

Getting Help

If you have any difficulties with log4j, post your question to CUBRID Forum at http://www.cubrid.org/?mid=forum&category=195533.