/*
* Copyright 2002-2007 the original author or authors.
*
* Licensed 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.
*/
package org.springframework.web.context;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Bootstrap servlet to start up Spring's root {@link WebApplicationContext}.
* Simply delegates to {@link ContextLoader}.
*
* <p>This servlet should have a lower <code>load-on-startup</code> value
* in <code>web.xml</code> than any servlets that access the root web
* application context.
*
* <p><i>Note that this class has been deprecated for containers implementing
* Servlet API 2.4 or higher, in favor of {@link ContextLoaderListener}.</i><br>
* According to Servlet 2.4, listeners must be initialized before load-on-startup
* servlets. Many Servlet 2.3 containers already enforce this behavior. If you
* use such a container, this servlet can be replaced with ContextLoaderListener.
*
* <p>Servlet 2.3 containers known to work with bootstrap listeners are:
* <ul>
* <li>Apache Tomcat 4.x+
* <li>Jetty 4.x+
* <li>Resin 2.1.8+
* <li>Orion 2.0.2+
* <li>BEA WebLogic 8.1 SP3
* </ul>
* For working with any of them, ContextLoaderListener is recommended.
*
* <p>Servlet 2.3 containers known <i>not</i> to work with bootstrap listeners are:
* <ul>
* <li>BEA WebLogic up to 8.1 SP2
* <li>IBM WebSphere 5.x
* <li>Oracle OC4J 9.0.3
* </ul>
* If you happen to work with such a server, this servlet has to be used.
*
* <p>So unfortunately, the only context initialization option that is compatible
* with <i>all</i> Servlet 2.3 containers is this servlet.
*
* <p>Note that a startup failure of this servlet will not stop the rest of the
* web application from starting, in contrast to a listener failure. This can
* lead to peculiar side effects if other servlets get started that depend on
* initialization of the root web application context.
*
* @author Juergen Hoeller
* @author Darren Davison
* @see ContextLoaderListener
* @see org.springframework.web.util.Log4jConfigServlet
*/
public class ContextLoaderServlet extends HttpServlet {
private ContextLoader contextLoader;
/**
* Initialize the root web application context.
*/
public void init() throws ServletException {
this.contextLoader = createContextLoader();
this.contextLoader.initWebApplicationContext(getServletContext());
}
/**
* Create the ContextLoader to use. Can be overridden in subclasses.
* @return the new ContextLoader
*/
protected ContextLoader createContextLoader() {
return new ContextLoader();
}
/**
* Return the ContextLoader used by this servlet.
* @return the current ContextLoader
*/
public ContextLoader getContextLoader() {
return this.contextLoader;
}
/**
* Close the root web application context.
*/
public void destroy() {
if (this.contextLoader != null) {
this.contextLoader.closeWebApplicationContext(getServletContext());
}
}
/**
* This should never even be called since no mapping to this servlet should
* ever be created in web.xml. That's why a correctly invoked Servlet 2.3
* listener is much more appropriate for initialization work ;-)
*/
public void service(HttpServletRequest request, HttpServletResponse response) throws IOException {
getServletContext().log(
"Attempt to call service method on ContextLoaderServlet as [" +
request.getRequestURI() + "] was ignored");
response.sendError(HttpServletResponse.SC_BAD_REQUEST);
}
public String getServletInfo() {
return "ContextLoaderServlet for Servlet API 2.3 " +
"(deprecated in favor of ContextLoaderListener for Servlet API 2.4)";
}
}