A simple example of log4j for Servlet
Description of the code:
Logger.getLogger(): Logger class is used for handling the majority of log operations and getLogger method is used for return a logger according to the value of the parameter. If the logger already exists, then the existing instance will be returned. If the logger is not already exist, then create a new instance.
log.info(): This method is used to check that the specified category is INFO enabled or not, if yes then it converts the massage passed as a string argument to a string by using appropriate object renderer of class ObjectRenderer.
LoggingServlet :
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
public class LoggingServlet extends HttpServlet {
private static Logger logger = Logger.getLogger(LoggingServlet.class);
protected void processRequest(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter writer = response.getWriter();
try {
logger.info("invoked the LoggingServlet...");
writer.println("Check your web server console...");
writer.flush();
writer.close();
} finally {
writer.close();
}
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}
Output:
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