November 2002
Intermediate to advanced
464 pages
14h 34m
English
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Using Commons Logging in JSP Pages
We’ve covered how to use the Commons Logging API within Java components, but we haven’t yet discussed how to use them in JSP pages. There are a number of ways to use the library within JSP pages, but we’ll just cover the two easiest approaches here.
The first approach is to use the same three steps defined earlier, this time performing them in the JSP page itself:
Import the Commons
LogandLogFactoryclasses.Define and initialize a logger variable for the page.
Start logging.
Example 15-8 illustrates this approach in a basic JSP page.
Example 15-8. Using Commons Logging in a JSP page
<%@ page import="org.apache.commons.logging.Log" %> <%@ page import="org.apache.commons.logging.LogFactory" %> <%-- Get a reference to the logger for this class --%> <% Log logger = LogFactory.getLog( this.getClass( ) ); %> <% logger.debug( "This is a debug message from a jsp" ); %> <html> <head> <title>Using Commons Logging in a JSP page</title> </head> <body> <% logger.info( "This is another log message in the jsp" ); %> There should be two log messages in the log file. </body> </html>
You must have the Commons Logging environment configured properly for this to work, just as when using it in the Java classes. Any JSP page that is part of the web application will be able to use the logging utilities. Because most containers use a different class loader for each web application, any JSP page that is not part of the log4j-configured web application may not be able ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.