Log4jInitializer.java

import java.io.IOException;
import java.net.URL;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.PropertyConfigurator;
import org.apache.log4j.helpers.Loader;


/**
 * Initializes log4j configuration based on environment properties
 * 
 * @author Varun Achar
 */
public class Log4jInitializer extends HttpServlet
{
	private static final long	serialVersionUID	= 1L;

	/**
	 * @see HttpServlet#HttpServlet()
	 */
	public Log4jInitializer()
	{
		super();
		// TODO Auto-generated constructor stub
	}

	/**
	 * @see Servlet#init(ServletConfig)
	 */
	@Override
	public void init(ServletConfig config) throws ServletException
	{
		String env = System.getenv("MY_ENVIRONMENT_VARIABLE");
		URL log4jConfig = Loader.getResource("log4j-" + env + ".properties");
		LogManager.resetConfiguration();
		PropertyConfigurator.configureAndWatch(new File(log4jConfig.getFile()).getAbsolutePath(), 60 * 1000);
	}

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
	{
		// Dummy Servlet. This doesn't execute because we're not mapping this servlet to any url
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
	{
		// Dummy Servlet. This doesn't execute because we're not mapping this servlet to any url
	}

}