Log4J - Revision history

Kevin at 09:39, 19 March 2009

2009-03-19T09:39:30Z

← Older revision		Revision as of 09:39, 19 March 2009
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	<param name="Subject" value="[System:Error] Application Error Message" />		<param name="Subject" value="[System:Error] Application Error Message" />
	<layout class="org.apache.log4j.PatternLayout">		<layout class="org.apache.log4j.PatternLayout">
	<param name="ConversionPattern"		<param name="ConversionPattern" value="%n%x%n%d{yyyy-MM-dd HH:mm:ss} [%-5p] %C.%M(%F:%L) %n%m%n" />
	value="%n%x%n%d{yyyy-MM-dd HH:mm:ss} [%-5p] %C.%M(%F:%L) %n%m%n" />
	</layout>		</layout>
	<filter class="org.apache.log4j.varia.LevelRangeFilter">		<filter class="org.apache.log4j.varia.LevelRangeFilter">
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	</appender>		</appender>
	</source>		</source>
	-With this ~~set up~~, all the log events other than <code>info</code> will be ignored by this appender. So the <code>only-info.log</code> file contains the log with <code>info</code> level.		-With this setup, all the log events other than <code>info</code> will be ignored by this appender. So the <code>only-info.log</code> file contains the log with <code>info</code> level.


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	</appender>		</appender>
	</source>		</source>
	-With this ~~set up~~, all the error anf fatal logs are stored in the <code>error-fatal.log</code> file		-With this setup, all the error anf fatal logs are stored in the <code>error-fatal.log</code> file


	=== Level Filtering for <code>SMTPAppender</code>		==== Level Filtering for <code>SMTPAppender</code> ====
	The level filtering with the above means does not work if the appender is <code>org.apache.log4j.net.SMTPAppender</code> and the ~~levels~~ to filter is lower ~~level~~ than <code>error</code>. <code>SMTPAppender</code> by default works only when the log event level is <code>error</code> or higher meaning <code>error</code> and <code>fatal</code>. To make it work with other levels than <code>error</code> and <code>fatal</code>, an <code>Evaluator</code> class has to be created and used. The <code>Evaluator</code> can be created by implementing <code>org.apache.log4j.spi.TriggeringEventEvaluator</code> interface. This interface has only one method which is <code>public boolean isTriggeringEvent(LoggingEvent event)</code>. So depending on the return value of this method in the ~~concret~~ class which implements the interface, the SMTPAppender may work even if the log event level is neither <code>error</code> nor <code>fatal</code>.		The level filtering with the above means does not work if the appender is <code>org.apache.log4j.net.SMTPAppender</code> and the level to filter is lower than <code>error</code> level. The <code>SMTPAppender</code> by default works only when the log event level is <code>error</code> or higher meaning <code>error</code> and <code>fatal</code>. To make it work with other levels than <code>error</code> and <code>fatal</code>, an <code>Evaluator</code> class has to be created and used. The <code>Evaluator</code> can be created by implementing <code>org.apache.log4j.spi.TriggeringEventEvaluator</code> interface. This interface has only one method which is <code>public boolean isTriggeringEvent(LoggingEvent event)</code>. So depending on the return value of this method in the concrete class which implements the interface, the SMTPAppender may work even if the log event level is neither <code>error</code> nor <code>fatal</code>.

	-Example: here is an example of <code>Evaluator</code> which checks if the the log event is <code>warn</code>.		-Example: here is an example of <code>Evaluator</code> which checks if the the log event is <code>warn</code>.
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	* org.apache.log4j.net.SMTPAppender.		* org.apache.log4j.net.SMTPAppender.
	*		*
	* @param ~~the~~		* @param event
	* LoggingEvent happened.		* the LoggingEvent happened.
	* @return true if the LoggingEvent is Level.WARN. false otherwise.		* @return true if the LoggingEvent is Level.WARN. false otherwise.
	*/		*/
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	</source>		</source>
	-With this setup file, any log event equals to or higher than <code>DEBUG</code> is displayed on the console.		-With this setup file, any log event equals to or higher than <code>DEBUG</code> is displayed on the console.
	-If it is <code>~~warn~~</code>, it is displayed on the console, and an email notification is sent with the subject of '[YourApplication] Warning!!!'.
	-If it is <code>~~error~~</code> or <code>~~fatal~~</code>, it is displayed on the console, and an email notification is sent with the subject of '[YourApplication] Error!!!'.		-If it is <code>WARN</code>, it is displayed on the console, and an email notification is sent with the subject of '[YourApplication] Warning!!!'.

			-If it is <code>ERROR</code> or <code>FATAL</code>, it is displayed on the console, and an email notification is sent with the subject of '[YourApplication] Error!!!'.

Kevin at 09:23, 19 March 2009

2009-03-19T09:23:18Z

Show changes

Kevin at 08:49, 18 March 2009

2009-03-18T08:49:11Z

← Older revision		Revision as of 08:49, 18 March 2009
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	==References==		==References==
	http://www.vipan.com/htdocs/log4jhelp.html		* http://logging.apache.org/log4j/1.2/publications.html

			* http://www.vipan.com/htdocs/log4jhelp.html

Kevin at 12:09, 23 October 2008

2008-10-23T12:09:56Z

← Older revision		Revision as of 12:09, 23 October 2008
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	value="///=========%n%x%n%d{yyyy-MM-dd HH:mm:ss} [%-5p] %C.%M(%F:%L) %n%m%n=========///%n"/>		value="///=========%n%x%n%d{yyyy-MM-dd HH:mm:ss} [%-5p] %C.%M(%F:%L) %n%m%n=========///%n"/>
	</layout>		</layout>
			</appender>

			<appender name="EMAIL" class="org.apache.log4j.net.SMTPAppender">
			<param name="BufferSize" value="512" />
			<param name="SMTPHost" value="email.server.com" />
			<param name="From" value="System Admin <admin@yoursite.com>" />
			<param name="To" value="developer@developers.email.com" />
			<param name="Subject" value="[System:Error] Application Error Message" />
			<layout class="org.apache.log4j.PatternLayout">
			<param name="ConversionPattern"
			value="%n%x%n%d{yyyy-MM-dd HH:mm:ss} [%-5p] %C.%M(%F:%L) %n%m%n" />
			</layout>
			<filter class="org.apache.log4j.varia.LevelRangeFilter">
			<param name="LevelMin" value="ERROR"/>
			<param name="LevelMax" value="FATAL"/>
			</filter>
	</appender>		</appender>

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	<level value="DEBUG"/>		<level value="DEBUG"/>
	<appender-ref ref="normal"/>		<appender-ref ref="normal"/>
			<appender-ref ref="EMAIL"/>
	</logger>		</logger>

	<root>		<root>
	<level value="INFO"/>		<level value="INFO"/>
	<appender-ref ref="normal"/>		<appender-ref ref="normal"/>

Kevin at 12:34, 6 October 2008

2008-10-06T12:34:03Z

← Older revision		Revision as of 12:34, 6 October 2008
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	[[Category:Java ~~logging frameworks~~]]		[[Category:Logging Frameworks (Java)]]
	==Configuration==		==Configuration==
	-Sample config text file		-Sample config text file

Kevin: New page: Category:Java logging frameworks ==Configuration== -Sample config text file # Set root category priority to DEBUG and set its only appender to A1 log4j.rootCategory=DEBUG, A1 # A...

2008-09-29T05:57:43Z

New page: Category:Java logging frameworks ==Configuration== -Sample config text file # Set root category priority to DEBUG and set its only appender to A1 log4j.rootCategory=DEBUG, A1 # A...

New page

[[Category:Java logging frameworks]]
==Configuration==
-Sample config text file

# Set root category priority to DEBUG and set its only appender to A1
log4j.rootCategory=DEBUG, A1

# A1 is set to be a ConsoleAppender (writes to system console).
log4j.appender.A1=org.apache.log4j.ConsoleAppender

# A1 uses PatternLayout.
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
#log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n
#log4j.appender.A1.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n
log4j.appender.A1.layout.ConversionPattern=%n%x%n%d{yyyy-MM-dd HH:mm:ss} [%-5p] %C.%M(%F:%L) %n%m%n%n

-Sample config xml file
<source lang="xml">
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">

<appender name="normal" class="org.apache.log4j.ConsoleAppender">
<param name="Threshold" value="DEBUG"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern"
value="///=========%n%x%n%d{yyyy-MM-dd HH:mm:ss} [%-5p] %C.%M(%F:%L) %n%m%n=========///%n"/>
</layout>
</appender>

<logger name="net.kevin" additivity="false">
<level value="DEBUG"/>
<appender-ref ref="normal"/>
</logger>

<root>
<level value="INFO"/>
<appender-ref ref="normal"/>
</root>




</log4j:configuration>
</source>

-Conversion characters:
* %m: Outputs your message.
* %p: Outputs the priority of the logging event.
* %r: Outputs the number of milliseconds elapsed since the start of the application until the creation of the logging event.
* %c: Outputs the category of the logging event. Example: For the category name "a.b.c", the pattern %c{2} will output "b.c". {2} means "output last two components of the dot-separated category name". If no {n} is there, full Category name is output by default.
* %t: Outputs the name of the thread that generated the logging event.
* %x: Outputs the nested diagnostic context (NDC) associated with the thread that generated the logging event. Useful when multiple clients are handled by separate threads such as in Java servlets.
* %n: Outputs the platform-dependent newline character(s). Preferable to specifying "\n" or "\r\n" etc.
* %%: Outputs a single percent sign.
* WARNING: The patterns below will slow down the execution of your program somewhat. Avoid unless execution speed is not an issue.
* %d: Outputs the date of the logging event. The date conversion specifier may be followed by a date format specifier enclosed between braces. Example: %d{HH:mm:ss,SSS} or %d{dd MMM yyyy HH:mm:ss,SSS}. If no date format specifier is given then ISO8601 format is assumed. The date format specifier admits the same syntax as the time pattern string of Java's SimpleDateFormat which is slow. For faster performance, use %d{ISO8601}, %d{ABSOLUTE}, %d{RELATIVE} (millisecs since program start, fastest) or %d{DATE} which use log4j's ISO8601DateFormat, AbsoluteTimeDateFormat, RelativeTimeDateFormat and DateTimeDateFormat date formatters respectively.
* %l: Outputs source code location information. Shortcut for %C.%M(%F:%L).
* %C: Outputs the fully-qualified class name of the caller issuing the logging request. Example: For the class name "org.apache.xyz.SomeClass", the pattern %C{1} will output "SomeClass". {1} means "output last one component of the fully-qualified class name". If no {n} is there, full class name is output by default.
* %M: Outputs the method name where the logging request was issued.
* %F: Outputs the file name where the logging request was issued.
* %L: Outputs the line number from where the logging request was issued.

==References==
http://www.vipan.com/htdocs/log4jhelp.html