Cloud Hosting Knowledgebase KB: How To Integrate Log 4 J Into A Java Application

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How to integrate Log4J into a Java application#

Its is best to log all messages to a individual log file instead of using the standard tomcat log files. Below is a quick tutorial to setup very simply logging using a JSP and a properties file. It is best to read the documentation available on the Log4J website to find out which is the best way to setup logging for your application.#

Download Log4J from the web http://logging.apache.org/site/binindex.cgi
Place the log4j****.jar into your WEB-INF/lib directory. This is found in dist\lib\ in the downloaded archive file.
Create a property file as listed below named "log4j.properties"

# Log4j configuration file.
 log4j.rootCategory=DEBUG, A1
 # Available levels are DEBUG, INFO, WARN, ERROR, FATAL
 log4j.appender.A1=org.apache.log4j.DailyRollingFileAppender
 log4j.appender.A1.file=logfile.log
 log4j.appender.A1.datePattern='.'yyyy-MM-dd
 log4j.appender.A1.append=true
 log4j.appender.A1.layout=org.apache.log4j.PatternLayout
 log4j.appender.A1.layout.ConversionPattern=%-5p %d{ISO8601} [%t] - %m%n

Create simple JSP, ensure to import the correct packages

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"
    import="org.apache.log4j.*"
    %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>TestWeb</title>
</head>
<body>
<%="Hello World"%>
<%

PropertyConfigurator.configure("log4j.properties");//This is best added to your startup page
Logger logger = Logger.getRootLogger();
logger.info("Hello World");
%>
</body>
</html>

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