001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache license, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the license for the specific language governing permissions and 015 * limitations under the license. 016 */ 017package org.apache.logging.log4j.core.web; 018 019import java.util.EnumSet; 020import java.util.Set; 021import javax.servlet.DispatcherType; 022import javax.servlet.FilterRegistration; 023import javax.servlet.ServletContainerInitializer; 024import javax.servlet.ServletContext; 025import javax.servlet.ServletException; 026 027/** 028 * In a Servlet 3.0 or newer environment, this initializer is responsible for starting up Log4j logging before anything 029 * else happens in application initialization. For consistency across all containers, if the effective Servlet major 030 * version of the application is less than 3.0, this initializer does nothing. 031 */ 032public class Log4jServletContainerInitializer implements ServletContainerInitializer { 033 034 @Override 035 public void onStartup(final Set<Class<?>> classes, final ServletContext servletContext) throws ServletException { 036 if (servletContext.getMajorVersion() > 2 && servletContext.getEffectiveMajorVersion() > 2 && 037 !"true".equalsIgnoreCase(servletContext.getInitParameter( 038 Log4jWebSupport.IS_LOG4J_AUTO_INITIALIZATION_DISABLED 039 ))) { 040 servletContext.log("Log4jServletContainerInitializer starting up Log4j in Servlet 3.0+ environment."); 041 042 final FilterRegistration.Dynamic filter = 043 servletContext.addFilter("log4jServletFilter", Log4jServletFilter.class); 044 if (filter == null) { 045 servletContext.log("WARNING: In a Servlet 3.0+ application, you should not define a " + 046 "log4jServletFilter in web.xml. Log4j 2 normally does this for you automatically. Log4j 2 " + 047 "web auto-initialization has been canceled."); 048 return; 049 } 050 051 final Log4jWebInitializer initializer = Log4jWebInitializerImpl.getLog4jWebInitializer(servletContext); 052 initializer.initialize(); 053 initializer.setLoggerContext(); // the application is just now starting to start up 054 055 servletContext.addListener(new Log4jServletContextListener()); 056 057 filter.setAsyncSupported(true); // supporting async when the user isn't using async has no downsides 058 filter.addMappingForUrlPatterns(EnumSet.allOf(DispatcherType.class), false, "/*"); 059 } 060 } 061}