| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| <!-- Generated by Apache Maven Doxia at 2017-09-17 --> |
| <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> |
| <head> |
| <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> |
| <title>Log4j Tag Library – Log4j Tag Library - Apache Log4j Tag Library</title> |
| <link rel="stylesheet" href="./css/bootstrap.min.css" type="text/css" /> |
| <link rel="stylesheet" href="./css/site.css" type="text/css" /> |
| <script type="text/javascript" src="./js/jquery.min.js"></script> |
| <script type="text/javascript" src="./js/bootstrap.min.js"></script> |
| <script type="text/javascript" src="./js/prettify.min.js"></script> |
| <script type="text/javascript" src="./js/site.js"></script> |
| <meta name="Date-Revision-yyyymmdd" content="20170917" /> |
| <meta http-equiv="Content-Language" content="en" /> |
| |
| </head> |
| <body class="composite"> |
| <a href="https://logging.apache.org/"> |
| <img class="logo-left" src="./images/ls-logo.jpg" alt="Apache logging services logo" /> |
| </a> |
| <img class="logo-right" src="./images/logo.png" alt="Apache log4j logo" /> |
| <div class="clear"></div> |
| |
| <div class="navbar"> |
| <div class="navbar-inner"> |
| <div class="container-fluid"> |
| <a class="brand" href="https://logging.apache.org/log4j/2.x/log4j-taglib/">Apache Log4j Tag Library ™</a> |
| <ul class="nav"> |
| <li> |
| |
| |
| <a href="https://wiki.apache.org/logging" class="external" target="_blank" title="Logging Wiki">Logging Wiki</a> |
| </li> |
| <li> |
| |
| |
| <a href="https://www.apache.org/" class="external" target="_blank" title="Apache">Apache</a> |
| </li> |
| <li> |
| <a href="../../../" title="Logging Services">Logging Services</a> |
| </li> |
| <li> |
| |
| |
| <a href="https://analysis.apache.org/dashboard/index/org.apache.logging.log4j:log4j" class="external" target="_blank" title="Sonar">Sonar</a> |
| </li> |
| <li> |
| |
| |
| <a href="https://github.com/apache/logging-log4j2" class="external" target="_blank" title="GitHub">GitHub</a> |
| </li> |
| <li> |
| |
| |
| <a href="http://www.apache.org/" class="external" target="_blank" title="Apache">Apache</a> |
| </li> |
| <li> |
| |
| |
| <a href="http://logging.apache.org/" class="external" target="_blank" title="Logging Services">Logging Services</a> |
| </li> |
| <li> |
| <a href="../index.html" title="Log4j">Log4j</a> |
| </li> |
| </ul> |
| </div> |
| </div> |
| </div> |
| |
| <div class="container-fluid"> |
| <table class="layout-table"> |
| <tr> |
| <td class="sidebar"> |
| <div class="well sidebar-nav"> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-home"></i>Apache Log4j™ 2</li> |
| <li class="none"> |
| <a href="../index.html" title="About">About</a> |
| </li> |
| <li class="none"> |
| <a href="../download.html" title="Download">Download</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../javadoc.html" title="Javadoc">Javadoc</a> |
| </li> |
| <li class="none"> |
| <a href="../maven-artifacts.html" title="Maven, Ivy, Gradle Artifacts">Maven, Ivy, Gradle Artifacts</a> |
| </li> |
| <li class="none"> |
| <a href="../runtime-dependencies.html" title="Runtime Dependencies">Runtime Dependencies</a> |
| </li> |
| <li class="none"> |
| <a href="../changelog.html" title="Changelog">Changelog</a> |
| </li> |
| <li class="none"> |
| <a href="../faq.html" title="FAQ">FAQ</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../performance.html" title="Performance">Performance</a> |
| </li> |
| <li class="none"> |
| <a href="../articles.html" title="Articles and Tutorials">Articles and Tutorials</a> |
| </li> |
| <li class="none"> |
| <a href="../thanks.html" title="Thanks">Thanks</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-pencil"></i>For Contributors</li> |
| <li class="none"> |
| <a href="../build.html" title="Building Log4j from Source">Building Log4j from Source</a> |
| </li> |
| <li class="none"> |
| <a href="../guidelines.html" title="Guidelines">Guidelines</a> |
| </li> |
| <li class="none"> |
| <a href="../javastyle.html" title="Style Guide">Style Guide</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-book"></i>Manual</li> |
| <li class="none"> |
| <a href="../manual/index.html" title="Introduction">Introduction</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/architecture.html" title="Architecture">Architecture</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/migration.html" title="Log4j 1.x Migration">Log4j 1.x Migration</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/api.html" title="Java API">Java API</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/scala-api.html" title="Scala API">Scala API</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/configuration.html" title="Configuration">Configuration</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/webapp.html" title="Web Applications and JSPs">Web Applications and JSPs</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/lookups.html" title="Lookups">Lookups</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/appenders.html" title="Appenders">Appenders</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/layouts.html" title="Layouts">Layouts</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/filters.html" title="Filters">Filters</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/async.html" title="Async Loggers">Async Loggers</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/garbagefree.html" title="Garbage-free Logging">Garbage-free Logging</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/jmx.html" title="JMX">JMX</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/logsep.html" title="Logging Separation">Logging Separation</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/extending.html" title="Extending Log4j">Extending Log4j</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/plugins.html" title="Plugins">Plugins</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/customconfig.html" title="Programmatic Log4j Configuration">Programmatic Log4j Configuration</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/customloglevels.html" title="Custom Log Levels">Custom Log Levels</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-tags"></i>Related Projects</li> |
| <li class="none"> |
| |
| |
| <a href="http://logging.apache.org/log4j/scala/index.html" class="external" target="_blank" title="Log4j-Scala">Log4j-Scala</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-tags"></i>Legacy</li> |
| <li class="none"> |
| |
| |
| <a href="http://logging.apache.org/log4j/1.2/" class="external" target="_blank" title="Log4j 1.2">Log4j 1.2</a> |
| </li> |
| <li class="none"> |
| |
| |
| <a href="http://logging.apache.org/log4j/log4j-2.3/" class="external" target="_blank" title="Log4j 2.3">Log4j 2.3</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-cog"></i>Components</li> |
| <li class="none"> |
| <a href="../log4j-api/index.html" title="API">API</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-core/index.html" title="Implementation">Implementation</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-jcl/index.html" title="Commons Logging Bridge">Commons Logging Bridge</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-1.2-api/index.html" title="Log4j 1.2 API">Log4j 1.2 API</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-slf4j-impl/index.html" title="SLF4J Binding">SLF4J Binding</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-jul/index.html" title="JUL Adapter">JUL Adapter</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-to-slf4j/index.html" title="Log4j 2 to SLF4J Adapter">Log4j 2 to SLF4J Adapter</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-flume-ng/index.html" title="Apache Flume Appender">Apache Flume Appender</a> |
| </li> |
| <li class="none active"> |
| <a href="../log4j-taglib/index.html" title="Log4j Tag Library">Log4j Tag Library</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-jmx-gui/index.html" title="Log4j JMX GUI">Log4j JMX GUI</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-web/index.html" title="Log4j Web Application Support">Log4j Web Application Support</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-appserver/index.html" title="Log4j Application Server Integration">Log4j Application Server Integration</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-nosql/index.html" title="Log4j NoSQL support">Log4j NoSQL support</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-iostreams/index.html" title="Log4j IO Streams">Log4j IO Streams</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-liquibase/index.html" title="Log4j Liquibase Binding">Log4j Liquibase Binding</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header">Component Documentation</li> |
| <li class="expanded"> |
| <a href="project-info.html" title="Component Information">Component Information</a> |
| <ul> |
| <li class="none active"> |
| <a href="index.html" title="About">About</a> |
| </li> |
| <li class="none"> |
| <a href="dependencies.html" title="Dependencies">Dependencies</a> |
| </li> |
| <li class="none"> |
| <a href="dependency-info.html" title="Dependency Information">Dependency Information</a> |
| </li> |
| <li class="none"> |
| <a href="dependency-convergence.html" title="Dependency Convergence">Dependency Convergence</a> |
| </li> |
| <li class="none"> |
| <a href="dependency-management.html" title="Dependency Management">Dependency Management</a> |
| </li> |
| <!-- Removing overall project item Team from component-specific menu --> |
| <!-- Removing overall project item Mailing Lists from component-specific menu --> |
| <!-- Removing overall project item Issue Management from component-specific menu --> |
| <!-- Removing overall project item Licenses from component-specific menu --> |
| <!-- Removing overall project item Source Code Management from component-specific menu --> |
| <li class="none"> |
| <a href="project-summary.html" title="Summary">Summary</a> |
| </li> |
| </ul> |
| </li> |
| <li class="collapsed"> |
| <a href="project-reports.html" title="Component Reports">Component Reports</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-info-sign"></i>Log4j Project Information</li> |
| <li class="none"> |
| <a href="../dependencies.html" title="Dependencies">Dependencies</a> |
| </li> |
| <li class="none"> |
| <a href="../dependency-convergence.html" title="Dependency Convergence">Dependency Convergence</a> |
| </li> |
| <li class="none"> |
| <a href="../dependency-management.html" title="Dependency Management">Dependency Management</a> |
| </li> |
| <li class="none"> |
| <a href="../team-list.html" title="Project Team">Project Team</a> |
| </li> |
| <li class="none"> |
| <a href="../mail-lists.html" title="Mailing Lists">Mailing Lists</a> |
| </li> |
| <li class="none"> |
| <a href="../issue-tracking.html" title="Issue Tracking">Issue Tracking</a> |
| </li> |
| <li class="none"> |
| <a href="../license.html" title="Project License">Project License</a> |
| </li> |
| <li class="none"> |
| <a href="../source-repository.html" title="Source Repository">Source Repository</a> |
| </li> |
| <li class="none"> |
| <a href="../project-summary.html" title="Project Summary">Project Summary</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-cog"></i>Log4j Project Reports</li> |
| <li class="none"> |
| <a href="../changes-report.html" title="Changes Report">Changes Report</a> |
| </li> |
| <li class="none"> |
| <a href="../jira-report.html" title="JIRA Report">JIRA Report</a> |
| </li> |
| <li class="none"> |
| <a href="../surefire-report.html" title="Surefire Report">Surefire Report</a> |
| </li> |
| <li class="none"> |
| <a href="../rat-report.html" title="RAT Report">RAT Report</a> |
| </li> |
| </ul> |
| </div> |
| <div id="poweredBy"> |
| <a href="http://maven.apache.org/" title="Built by Maven" class="poweredBy"> |
| <img class="poweredBy" alt="Built by Maven" src="./images/maven-feather.png" /> |
| </a> |
| </div> |
| </td> |
| <td class="content"> |
| <!-- vim: set syn=markdown : --> |
| <!-- Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. --><h1>Log4j Tag Library</h1> |
| <p>The Log4j Log Tag Library creates the capability of inserting log statements in JSPs without the use of Java scripting. It uses the standard Log4j 2 API to log messages according to your Log4j configuration.</p> |
| <p>This tag library is based on the <a class="externalLink" href="http://jakarta.apache.org/taglibs/log/">Jakarta Commons Log Taglib</a> by Joseph Ottinger and James Strachan. For the most part, logging tags written against Jakarta Commons Log Taglib should work against this library as well. However, the “category” attribute from Jakarta has become the “logger” attribute in this library.</p> |
| <div class="section"> |
| <h2><a name="Requirements"></a>Requirements</h2> |
| <p>The Log4j Tag Library requires at least Servlet 2.5 (or Java EE 5), at least JSP 2.1 (or Java EE 5), and is dependent on the Log4j 2 API. For more information, see <a href="../runtime-dependencies.html">Runtime Dependencies</a>.</p> |
| <p><span class="label label-important">Important Note!</span> For performance reasons, containers often ignore certain JARs known not to contain TLDs and do not scan them for TLD files. Importantly, Tomcat 7 <7.0.43 ignores all JAR files named log4j*.jar, which prevents the JSP tag library from being automatically discovered. This does not affect Tomcat 6.x and has been fixed in Tomcat 7.0.43, Tomcat 8, and later. In Tomcat 7 <7.0.43 you will need to change <tt>catalina.properties</tt> and remove “log4j*.jar” from the <tt>jarsToSkip</tt> property. You may need to do something similar on other containers if they skip scanning Log4j JAR files.</p></div> |
| <div class="section"> |
| <h2><a name="Usage"></a>Usage</h2> |
| <p>In accordance with the <a href="../log4j-api/apidocs/org/apache/logging/log4j/Logger.html">Logger</a> API, this tag library has tags to support the following logging calls: “catching”, “entry”, “exit”, “log”, “trace”, “debug”, “info”, “warn”, “error”, and “fatal”. The “trace” tag was not supported in Jakarta Commons Log Taglib. The “setLogger”, “catching”, “entry”, and “trace” tags are new to this library. This tag library also supports the conditional tag “ifEnabled” (new) and troubleshooting tag “dump” (existed in Jakarta Commons Log Taglib).</p> |
| <p>By default, this tag library uses a different Logger for each JSP named after the JSP ID. You can customize the Logger in any of the logging tags or the “ifEnabled” tag with the “logger” attribute. You can also use the “setLogger” tag to specify the Logger that should apply for the rest of a JSP’s execution. If the “setLogger” tag comes before any other logging tags in a JSP, the default Logger for that JSP will not be created, but instead the specified logger is the only one that will be used.</p> |
| <p>Every effort was made to optimize these tags and ensure decent performance, but users of this library should keep in mind that the creation and execution of JSP tags adds significant overhead to the standard Log4j method calls. While the “trace”, “debug”, and “info” options are available in this library, their uses are not nano-second order of magnitude with logging off that users may be used to with standard Log4j method calls. Therefore, they should be used sparingly. Use of the “ifEnabled” tag does not improve this performance; this tag is available to conditionally evaluate other actions in addition to logging actions.</p> |
| <p>For detailed documentation of each tag, see the <a href="tagreference.html">Tag Library Reference</a> or the <a href="tlddoc/index.html">TLDDoc Documentation</a>.</p></div> |
| </td> |
| </tr> |
| </table> |
| </div> |
| |
| <div class="footer"> |
| <p>Copyright © 1999-2017 <a class="external" href="https://www.apache.org/">The Apache Software Foundation</a>. All Rights Reserved.</p> |
| <p>Apache Logging, Apache Log4j, Log4j, Apache, the Apache feather logo, and the Apache Logging project logo are trademarks of The Apache Software Foundation.</p> |
| <p>Site powered by <a class="external" href="http://getbootstrap.com/">Twitter Bootstrap</a>. Icons from <a class="external" href="http://glyphicons.com/">Glyphicons Free</a>.</p> |
| </div> |
| </div> |
| </body> |
| </html> |
