Initialization servlet
It is also possible to use a special servlet for log4j initialization. Here is an example,
package com.foo;
import org.apache.log4j.PropertyConfigurator;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.io.IOException;
public class Log4jInit extends HttpServlet {
public
void init() {
String prefix = getServletContext().getRealPath("/");
String file = getInitParameter("log4j-init-file");
// if the log4j-init-file is not set, then no point in trying
if(file != null) {
PropertyConfigurator.configure(prefix+file);
}
}
public
void doGet(HttpServletRequest req, HttpServletResponse res) {
}
}
Define the following servlet in the web.xml file for your web-application.
<servlet>
<servlet-name>log4j-init</servlet-name>
<servlet-class>com.foo.Log4jInit</servlet-class>
<init-param>
<param-name>log4j-init-file</param-name>
<param-value>WEB-INF/classes/log4j.lcf</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
Writing an initialization servlet is the most flexible way for initializing log4j. There are no constraints on the code you can place in the init() method of the servlet.
