Log4j Properties

Log4j configuration with log4j.xml

Logging to console:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration debug="true"
	xmlns:log4j='http://jakarta.apache.org/log4j/'>
 
	<appender name="console" 
	            class="org.apache.log4j.ConsoleAppender">
	    <layout class="org.apache.log4j.PatternLayout">
		<param name="ConversionPattern" 
		  value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - 
		              %m%n" />
	    </layout>
	</appender>
 
	<root>
		<level value="DEBUG" />
		<appender-ref ref="console" />
	</root>
</log4j:configuration>

Here logging level is set at DEBUG, Appender is console,Layout is Pattern with timestamp.

Logging to file: 

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration debug="true"
	xmlns:log4j='http://jakarta.apache.org/log4j/'>
 
	<appender name="file" 
	     class="org.apache.log4j.RollingFileAppender">
	   <param name="append" value="false" />
	   <param name="maxFileSize" value="10MB" />
	   <param name="maxBackupIndex" value="10" />
	   
	   <param name="file" value="D:/AppLog/applog.log" />
	   <layout class="org.apache.log4j.PatternLayout">
		<param name="ConversionPattern" 
			value="%d{yyyy-MM-dd HH:mm:ss} 
			      %-5p %c{1}:%L - %m%n" />
	   </layout>
	</appender>
 
	<root>
		<level value="ERROR" />
		<appender-ref ref="file" />
	</root>
 
</log4j:configuration>

Here logging level is set at ERROR, Appender is file, Layout is Pattern with timestamp.

Logging to DB:

Suppose we have table in our DB: 

CREATE TABLE LOG_TABLE
   (USER_ID VARCHAR(10) NOT NULL,
    DATED   DATE NOT NULL,
    LOGGER  VARCHAR(50) NOT NULL,
    LEVEL   VARCHAR(10) NOT NULL,
    MESSAGE VARCHAR(1000) NOT NULL
   );

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration debug="true"
	xmlns:log4j='http://jakarta.apache.org/log4j/'>

<appender name="DB" class="org.apache.log4j.jdbc.JDBCAppender">
   <param name="url" value="jdbc:mysql://localhost/DBNAME"/>
   <param name="driver" value="com.mysql.jdbc.Driver"/>
   <param name="user" value="username"/>
   <param name="password" value="password"/>
   <param name="sql" value="INSERT INTO LOG_TABLE VALUES('%x',
                             '%d','%C','%p','%m')"/>
   <layout class="org.apache.log4j.PatternLayout">
   </layout>

</appender>

	<root>
		<level value="ERROR" />
		<appender-ref ref="DB" />
	</root>
</log4j:configuration>

Here logging level is set at ERROR, Appender is DB, Layout is Pattern with timestamp.