Log4j在jsp中的应用

bosschen

浏览: 197238 次
性别:
来自: 北京

最近访客更多访客>>

冰~水

hiroada

cunzhangok

zincal8

博主相关

博客

微博

相册

留言

关于我

文章分类

全部博客 (143)

社区版块

存档分类

虽然在JSP中打印日志是大家都不想使用的。但由于个别需求需要对JSP进行维护的时候使用日志打印是首选之道。

下面转自国外网站介绍在JSP中使用LOG4J的实例。

原文地址：http://www.mobilefish.com/developer/log4j/log4j_quickguide_jsp.html

Apply log4j within jsp.

Information

none

Operating system used

Windows XP Home Edition Version 5.1 SP 2

Software prerequisites

Tomcat

Jakarta log tag library

Log4j 1.2.9

Procedure

Download the Jakarta log tag library: jakarta-taglibs-log-1.0.zip
Extract this archive file, e.g.: C:\Tools\jakarta-taglibs-log-1.0

The archive contains the following files:

LICENSE

log-doc.war

log-examples.war

README

taglibs-log.jar

taglibs-log.tld
Download Log4j 1.2.9: logging-log4j-1.2.9.zip
Extract this archive file, e.g.: C:\Tools\logging-log4j-1.2.9

The archive contains serveral files. The most important one is: C:\Tools\logging-log4j-1.2.9\dist\lib\log4j-1.2.9.jar
Install Tomcat. Follow guide "Installing Tomcat 4.1.31".
Create a simple a Tomcat web application called "demo":
- Create the following directories inside the Tomcat "webapps" directory:
  
  C:\Tools\Tomcat 4.1\webapps\demo
  
  C:\Tools\Tomcat 4.1\webapps\demo\WEB-INF
  
  C:\Tools\Tomcat 4.1\webapps\demo\WEB-INF\classes
  
  C:\Tools\Tomcat 4.1\webapps\demo\WEB-INF\lib
- Copy the tag library descriptor file "taglibs-log.tld" into WEB-INF.
- Copy the tag library JAR file "taglibs-log.jar" into WEB-INF/lib.
- Copy the log4j JAR file "log4j-1.2.9.jar" into WEB-INF/lib.
- Create a web.xml file in the WEB-INF directory:
  
  <?xml version="1.0"?>
  
  <!DOCTYPE web-app
  
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
  
    "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
  
  <web-app>
  
     <display-name>Demonstration log4j usage in jsp</display-name>
  
     <welcome-file-list>
  
        <welcome-file>index.jsp</welcome-file>
  
     </welcome-file-list>
  
     <taglib>
  
        <taglib-uri>http://jakarta.apache.org/taglibs/log-1.0</taglib-uri>
  
        <taglib-location>/WEB-INF/taglibs-log.tld</taglib-location>
  
     </taglib>
  
  </web-app>
  
  Note: You MUST add a <taglib> element in the web.xml file:
  
  <taglib>
  
     <taglib-uri>http://jakarta.apache.org/taglibs/log-1.0</taglib-uri>
  
     <taglib-location>/WEB-INF/log.tld</taglib-location>
  
  </taglib>
- Create a log4j.properties file in the WEB-INF/classes directory:
  
  # ***** Set root logger level to DEBUG and its two appenders to stdout and R.
  
  log4j.rootLogger=debug, stdout, R
  
  # ***** stdout is set to be a ConsoleAppender.
  
  log4j.appender.stdout=org.apache.log4j.ConsoleAppender
  
  # ***** stdout uses PatternLayout.
  
  log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
  
  log4j.appender.stdout.layout.ConversionPattern=%d [%c] %p - %m%n
  
  # ***** R is set to be a RollingFileAppender.
  
  log4j.appender.R=org.apache.log4j.RollingFileAppender
  
  log4j.appender.R.File=${catalina.home}/logs/demo.log
  
  # ***** Max file size is set to 100KB
  
  log4j.appender.R.MaxFileSize=100KB
  
  # ***** Keep one backup file
  
  log4j.appender.R.MaxBackupIndex=1
  
  # ***** R uses PatternLayout.
  
  log4j.appender.R.layout=org.apache.log4j.PatternLayout
  
  log4j.appender.R.layout.ConversionPattern=%d [%c] %p - %m%n
  
  Note:
  
  The location of the log file is set in:
  
  log4j.appender.R.File=${catalina.home}/logs/demo.log
- Create two jsp files in the C:\Tools\Tomcat 4.1\webapps\demo directory:
  
  File 1: index.jsp
  
  <%@ taglib uri="http://jakarta.apache.org/taglibs/log-1.0" prefix="log" %>
  
  <html>
  
  <head>
  
     <title>Demonstration log4j usage in jsp</title>
  
  </head>
  
  <body>
  
  
  
  <log:debug>Show DEBUG message.</log:debug>
  
  <log:info>Show INFO message.</log:info>
  
  <log:warn>Show WARN message.</log:warn>
  
  <log:error>Show ERROR message.</log:error>
  
  <log:fatal>Show FATAL message.</log:fatal>
  
  
  
  <log:fatal>Message embedded within the open and close tags.</log:fatal>
  
  <log:fatal message="Message passed as an attribute to the tag" />
  
  <log:fatal category="com.mobilefish.demo.index">
  
     Using category attribute.
  
  </log:fatal>
  
  <b>
  
     The log messages are shown in the Tomcat console and in the
  
     ${catalina.home}/logs/demo.log file.
  
  </b>
  
  </body>
  
  </html>
  
  File 2: test.jsp
  
  <%@ page import="org.apache.log4j.Logger" %>
  
  <html>
  
  <head>
  
     <title>Demonstration log4j usage in jsp</title>
  
  </head>
  
  <body>
  
  <%
  
  Logger log = Logger.getLogger("com.mobilefish.demo.test");
  
  log.debug("Show DEBUG message");
  
  log.info("Show INFO message");
  
  log.warn("Show WARN message");
  
  log.error("Show ERROR message");
  
  log.fatal("Show FATAL message");
  
  %>
  
  <b>
  
     The log messages are shown in the Tomcat console and in the
  
     ${catalina.home}/logs/demo.log file.
  
  </b>
  
  </body>
  
  </html>
(Re)start Tomcat.
Access the index.jsp file:

http://localhost:8080/demo/index.jsp
The following log messages are shown in the Tomcat console and in the ${catalina.home}/logs/demo.log file.

2006-06-03 17:28:43,379 [root] DEBUG - Show DEBUG message.

2006-06-03 17:28:43,409 [root] INFO - Show INFO message.

2006-06-03 17:28:43,409 [root] WARN - Show WARN message.

2006-06-03 17:28:43,409 [root] ERROR - Show ERROR message.

2006-06-03 17:28:43,419 [root] FATAL - Show FATAL message.

2006-06-03 17:28:43,419 [root] FATAL - Message embedded within the open and close tags.

2006-06-03 17:28:43,419 [root] FATAL - Message passed as an attribute to the tag

2006-06-03 17:28:43,419 [com.mobilefish.demo.index] FATAL - Using category attribute.
Access the test.jsp file:

http://localhost:8080/demo/test.jsp
The following log messages are shown in the Tomcat console and in the ${catalina.home}/logs/demo.log file.

2006-06-03 17:55:43,379 [com.mobilefish.com.test] DEBUG - Show DEBUG message.

2006-06-03 17:55:43,409 [com.mobilefish.com.test] INFO - Show INFO message.

2006-06-03 17:55:43,409 [com.mobilefish.com.test] WARN - Show WARN message.

2006-06-03 17:55:43,409 [com.mobilefish.com.test] ERROR - Show ERROR message.

2006-06-03 17:55:43,419 [com.mobilefish.com.test] FATAL - Show FATAL message.
Change the root logger level to WARN in the log4j.properties file and restart Tomcat:

log4j.rootLogger=warn, stdout, R

When the index.jsp page is reloaded in your browser only the following messages are shown:

2006-06-03 17:48:43,409 [root] WARN - Show WARN message.

2006-06-03 17:48:43,409 [root] ERROR - Show ERROR message.

2006-06-03 17:48:43,419 [root] FATAL - Show FATAL message.

2006-06-03 17:48:43,419 [root] FATAL - Message embedded within the open and close tags.

2006-06-03 17:48:43,419 [root] FATAL - Message passed as an attribute to the tag

2006-06-03 17:48:43,419 [com.mobilefish.demo.index] FATAL - Using category attribute.