RE: How to use Log4j with a startup logging servlet

[Jenkins, David]

Hi Eric, here's how use Logging to provide method call logging.

import org.apache.log4j.Category;

public class myclass {

  private static final Category log = Category.getInstance(myclass .class);

  public void mymethod() {
try {
  log.debug("enter mymethod");
}
finally {
  log.debug("exit mymethod");
}
  }
}

Dave

-Original Message-
From: Eric L. Ma [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, 16 January 2002 3:58 p.m.
To: 'Struts Users Mailing List'
Subject: RE: How to use Log4j with a startup logging servlet


Thanks, gentlemen.  I start to get the idea but am still fuzzy on how to
issue logging requests in my custom Action classes.  Do I have to
declare a static Category variable in each and every Action class I
write?  Please share some code on how logging is actually done, now that
I know how to set up the startup servlet.

Eric

-Original Message-
From: Eric Ma [mailto:[EMAIL PROTECTED]] 
Sent: Tuesday, January 15, 2002 12:33 PM
To: [EMAIL PROTECTED]
Subject: How to use Log4j with a startup logging servlet

I want to use Log4J for logging exceptions thrown in a Struts-based web
app.  After searching through this list, I found 2 common solutions:

1. Extend the Struts ActionServlet and override the init() method to set
up a Log4J Category.  Then in any custom Action class I can just call
servlet.Category.debug() (let's assume Category is a protected or public
variable).

2. Write a separate startup servlet and again set up LOG4J in the init()
method.  But my question is, how do I invoke this servlet from my custom
Action class?  Do I need to do a RequestDispatcher.forward() to the
servlet when an exception is thrown?  Then how do I get back to the page
I am on to display the error message?

Eric Ma


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RE: How to use Log4j with a startup logging servlet

[Eric L. Ma]

Thanks, gentlemen.  I start to get the idea but am still fuzzy on how to
issue logging requests in my custom Action classes.  Do I have to
declare a static Category variable in each and every Action class I
write?  Please share some code on how logging is actually done, now that
I know how to set up the startup servlet.

Eric

-Original Message-
From: Eric Ma [mailto:[EMAIL PROTECTED]] 
Sent: Tuesday, January 15, 2002 12:33 PM
To: [EMAIL PROTECTED]
Subject: How to use Log4j with a startup logging servlet

I want to use Log4J for logging exceptions thrown in a Struts-based web
app.  After searching through this list, I found 2 common solutions:

1. Extend the Struts ActionServlet and override the init() method to set
up a Log4J Category.  Then in any custom Action class I can just call
servlet.Category.debug() (let's assume Category is a protected or public
variable).

2. Write a separate startup servlet and again set up LOG4J in the init()
method.  But my question is, how do I invoke this servlet from my custom
Action class?  Do I need to do a RequestDispatcher.forward() to the
servlet when an exception is thrown?  Then how do I get back to the page
I am on to display the error message?

Eric Ma


--

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RE: How to use Log4j with a startup logging servlet

[Alex Colic]

Hi,

I have used option two.

The code for my servlet is below. It works for me. If you have any
suggestions, enhancements please send me a note.

Alex



package com.sirius.struts.action;

import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.log4j.*;


public class genericLog4JServlet extends HttpServlet
{

  private static final Category
cat=Category.getInstance(genericLog4JServlet.class.getName());

  public void init() throws javax.servlet.ServletException
{

  ServletContext context=getServletContext();

  /**
  * Get the Log4J settings and the logging paramters
  */
 try
  {
String strLogSetting
=(String)this.getInitParameter("Log4JFileSetting");

PropertyConfigurator.configure(context.getResource(strLogSetting));
  }
catch(java.net.MalformedURLException e){e.printStackTrace();}

}
}

-Original Message-
From: Eric Ma [mailto:[EMAIL PROTECTED]]
Sent: January 15, 2002 12:33 PM
To: [EMAIL PROTECTED]
Subject: How to use Log4j with a startup logging servlet


I want to use Log4J for logging exceptions thrown in a Struts-based web app.
After searching through this list, I found 2 common solutions:

1. Extend the Struts ActionServlet and override the init() method to set up
a Log4J Category.  Then in any custom Action class I can just call
servlet.Category.debug() (let's assume Category is a protected or public
variable).

2. Write a separate startup servlet and again set up LOG4J in the init()
method.  But my question is, how do I invoke this servlet from my custom
Action class?  Do I need to do a RequestDispatcher.forward() to the servlet
when an exception is thrown?  Then how do I get back to the page I am on to
display the error message?

Eric Ma


--

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are not the intended recipient (or have received this e-mail in error)
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unauthorized copying, disclosure or distribution of the material in this
e-mail is strictly forbidden.




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RE: How to use Log4j with a startup logging servlet

[Jenkins, David]

If you're using Tomcat 4.0.x then the documentation shows how to use a
servlet to configure Log4J. Essentially you create a normal servlet, slap it
in your web.xml and configure it to load on startup.
I do this in all my web apps and also use the same method to init Velocity.
Here's a sample web.xml entry

  
log4j-init
Log4jInit

  log4j-init-file
  WEB-INF/classes/log4j.properties

1
  

and the init method from the servlet

  public void init() throws ServletException {
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);
}
getServletContext().log("logging to: "+prefix+file);
  }



-Original Message-
From: Eric Ma [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, 16 January 2002 6:33 a.m.
To: [EMAIL PROTECTED]
Subject: How to use Log4j with a startup logging servlet


I want to use Log4J for logging exceptions thrown in a Struts-based web app.
After searching through this list, I found 2 common solutions:

1. Extend the Struts ActionServlet and override the init() method to set up
a Log4J Category.  Then in any custom Action class I can just call
servlet.Category.debug() (let's assume Category is a protected or public
variable).

2. Write a separate startup servlet and again set up LOG4J in the init()
method.  But my question is, how do I invoke this servlet from my custom
Action class?  Do I need to do a RequestDispatcher.forward() to the servlet
when an exception is thrown?  Then how do I get back to the page I am on to
display the error message?

Eric Ma


--

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are not the intended recipient (or have received this e-mail in error)
please notify the sender immediately and destroy this e-mail. Any
unauthorized copying, disclosure or distribution of the material in this
e-mail is strictly forbidden.



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Re: How to use Log4j with a startup logging servlet

[Thomas Eichberger]

Hi,

I use Log4J, but don't understand your question exactly. I think it's 
easier than you think;-)

In my action classes and servlets and so on I have the usual line:

static Category cat = Category.getInstance( SuchAction.class.getName() );





in web.xml I have:

   
 log4j-init
 at.tanzforum.homepage.artists.Log4JInit

 
   log4j-init-file
   WEB-INF/classes/log4j.lcf
 

 1
   


as described in the documentation of Log4J (they explain there how to use 
Log4J with TomCat)


and finally I have that Servlet:

package at.tanzforum.homepage.artists;


import java.io.*;
import java.util.*;
import java.net.*;

import javax.servlet.*;
import javax.servlet.http.*;

import java.sql.*;

import org.apache.log4j.*;



public class Log4JInit extends HttpServlet {

static Category cat = Category.getInstance( MainServlet.class.getName() );

   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);
   cat.info( "Log4J configured by file " + prefix + file );
 }
   }

   public
   void doGet(HttpServletRequest req, HttpServletResponse res) {
   }
}




Ciao

Thomas










At 12:33 15.01.2002 -0500, you wrote:
>I want to use Log4J for logging exceptions thrown in a Struts-based web 
>app.  After searching through this list, I found 2 common solutions:
>
>1. Extend the Struts ActionServlet and override the init() method to set 
>up a Log4J Category.  Then in any custom Action class I can just call 
>servlet.Category.debug() (let's assume Category is a protected or public 
>variable).
>
>2. Write a separate startup servlet and again set up LOG4J in the init() 
>method.  But my question is, how do I invoke this servlet from my custom 
>Action class?  Do I need to do a RequestDispatcher.forward() to the 
>servlet when an exception is thrown?  Then how do I get back to the page I 
>am on to display the error message?
>
>Eric Ma
>
>
>--
>
>This e-mail may contain confidential and/or privileged information. If you 
>are not the intended recipient (or have received this e-mail in error) 
>please notify the sender immediately and destroy this e-mail. Any 
>unauthorized copying, disclosure or distribution of the material in this 
>e-mail is strictly forbidden.
>
>
>
>--
>To unsubscribe, e-mail:   
>For additional commands, e-mail: 

Thomas Eichberger - Software und Schulungen - Spezialisiert auf Java
A-1230 WIEN, Endresstr. 103/3
phone/box/fax: 01-8861685 Web: www.java.at E-Mail: [EMAIL PROTECTED]
"Every job is a self-portrait of the person who did it. Autograph yours 
with excellence."
"For every complex question there is an answer that is clear, simple and wrong."


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RE: How to use Log4j with a startup logging servlet

[McDowell, Mark]

I use method 2, but it doesn't require a call into that servlet.  I just use
it to initialize log4j.  After this servlet loads, I just call log4j object
methods, and it works.  I believe (someone correct me if I'm wrong) that the
servlet loads in the same JVM, so you have access to its objects in the
other servlets...

Mark

-Original Message-
From: Eric Ma [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 15, 2002 11:33 AM
To: [EMAIL PROTECTED]
Subject: How to use Log4j with a startup logging servlet


I want to use Log4J for logging exceptions thrown in a Struts-based web app.
After searching through this list, I found 2 common solutions:

1. Extend the Struts ActionServlet and override the init() method to set up
a Log4J Category.  Then in any custom Action class I can just call
servlet.Category.debug() (let's assume Category is a protected or public
variable).

2. Write a separate startup servlet and again set up LOG4J in the init()
method.  But my question is, how do I invoke this servlet from my custom
Action class?  Do I need to do a RequestDispatcher.forward() to the servlet
when an exception is thrown?  Then how do I get back to the page I am on to
display the error message?

Eric Ma


--

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are not the intended recipient (or have received this e-mail in error)
please notify the sender immediately and destroy this e-mail. Any
unauthorized copying, disclosure or distribution of the material in this
e-mail is strictly forbidden.



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