Log4j in Servlets

[Kedar Kachare]

How to use Log4j to create log files using file appender in a Servlet? Also, how to make that Servlet read the log4j.propertie s file?


I have tried following:

My web.xml( I use Eclipse europa)

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">

        <display-name>ClientSkill_Log4j</display-name>

        <welcome-file-list>

          <welcome-file>index.html</welcome-file>

          <welcome-file>index.htm</welcome-file>

          <welcome-file>index.jsp</welcome-file>

          <welcome-file>default.html</welcome-file>

          <welcome-file>default.htm</welcome-file>

          <welcome-file>default.jsp</welcome-file>

        </welcome-file-list>

       

        <servlet>

          <description>Description</description>

          <display-name>Display name</display-name>
         

          <servlet-name>ClientSkillServlet</servlet-name>

          <servlet-class>HTML_Generator</servlet-class>

         

          <init-param>

              <param-name>log4j.properties</param-name>

              <param-value>WEB-INF/log4j.properties</param-value>

          </init-param>

        </servlet>

       

        <servlet-mapping>

          <servlet-name>ClientSkillServlet</servlet-name>

          <url-pattern>/</url-pattern>

        </servlet-mapping>
</web-app>

My log4j.propertie s file:-

      # Configures Log4j as the Tomcat system logger
      #
      #
      # Configure the logger to output info level messages into a log file.
      #
      log4j.rootLogger=INFO, R
      #
      # To continue using the "catalina.out" file (which grows forever),
      # comment out the above line and uncomment the next.
      #
      log4j.rootLogger=ERROR, A1
      #
      # Configuration for standard output ("catalina.out").
      #
      log4j.appender.A1=org.apache.log4j.ConsoleAppender 
      log4j.appender.A1.layout=org.apache.log4j.PatternL  ayout
      #
      # Print the date in ISO 8601 format
      #
      log4j.appender.A1.layout.ConversionPattern=%d [%t] %-5p %c - %m%n
      #
      # Configuration for a rolling log file ("tomcat.log").
      #
      log4j.appender.R=org.apache.log4j.FileAppender
      # Edit the next line to point to your logs directory.
      # The last part of the name is the log file name.
      #
      log4j.appender.R.File=D:\DATA\tomcat.log
      log4j.appender.R.layout=org.apache.log4j.PatternLa  yout
      #
      # Print the date in ISO 8601 format
      #
      log4j.appender.R.layout.ConversionPattern=%d [%t] %-5p %c - %m%n
      # Application logging options
      #
      #log4j.logger.org.apache=DEBUG
      #log4j.logger.org.apache=INFO
      #log4j.logger.org.apache.struts=DEBUG
      #log4j.logger.org.apache.struts=INFO

and My servlet code is:

      import java.sql.*;
      import java.io.*;
      import javax.servlet.*;
      import javax.servlet.http.*;
      import org.apache.log4j.*;

      public class HTML_Generator extends HttpServlet

      {
          private static Logger logger =Logger.getLogger(HTML_Generator.class);
          public void init() throws ServletException

          {

              // Put your code here

              String prefix = getServletContext().getRealPath("/");

              String file = getInitParameter("log4j.properties");

              if(file != null)

              {

                  PropertyConfigurator.configure(prefix+file);
              }

          }

          public void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException, IOException

          {

                  PrintWriter pw = resp.getWriter();

                  Connection conn = null;

                  ResultSet rs = null;

                  Statement stmt = null;

                  pw.println("Check your web server console...");

                  System.out.println("Insde doPost()");

                  pw.flush();

                  pw.close();

                  try

                  {

                      Class.forName("<driver name>");

                      conn = DriverManager.getConnection("<url>","<username>","<password>");

                      stmt = conn.createStatement();

                      rs = stmt.executeQuery("<my query>" );

                      int numColumns = rs.getMetaData().getColumnCount();

                      int i=0;

                      pw.println("<form name=\"Form2\" method=\"POST\" action=\"http://localhost/servlet/<target-servlet(running fine)>\">");

                      while (rs.next())

                      {

                          for (i = 1 ; i < numColumns ; i++ )

                              {

                                  <my action>

                              }

                      }

                     

                  }

                  catch(SQLException sqle)

                  {

                      sqle.printStackTrace();

                  }

                  catch(Exception exc)

                  {

                      exc.printStackTrace();

                  }

                  try

                  {

                      rs.close();

                      stmt.close();

                      conn.close();

                  }catch(SQLException sqle){

                      sqle.printStackTrace();

                  }catch(Exception exc){

                      exc.printStackTrace();

                  }

          }

      }

Thanks in advance,
Kedar

[Dököll]

Greetings!

I fetched below and thought it could be of use:

Using the Log4J

http://www.roseindia.net/tutorials/log4j/writer-appender-log4j.shtml

Let us know if it worked:-)