//Log4j from Apache is required
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
public class LogFilter implements Filter {
private FilterConfig config;
private Logger log;
/** Creates new RequestFilter */
public LogFilter() {
}
public void init(FilterConfig filterConfig) throws ServletException {
this.config = filterConfig;
//load the configuration for this application's loggers using the
// servletLog.properties file
PropertyConfigurator.configure(config.getServletContext().getRealPath(
"/")
+ "WEB-INF/classes/servletLog.properties");
log = Logger.getLogger(LogFilter.class);
log.info("Logger instantiated in " + getClass().getName());
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws java.io.IOException, ServletException {
HttpServletRequest req = null;
String id = config.getInitParameter("log-id");
if (id == null)
id = "unknown";
if (log != null && (request instanceof HttpServletRequest)) {
req = (HttpServletRequest) request;
log.info("Log id:" + id + ": Request received from: "
+ req.getRemoteHost() + " for " + req.getRequestURL());
}
chain.doFilter(request, response);
}// doFilter
public void destroy() {
/*
* called before the Filter instance is removed from service by the web
* container
*/
log = null;
}
}