/*
* Copyright 2012-2014 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.boot.context.web;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.boot.builder.ParentContextApplicationContextInitializer;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext;
import org.springframework.context.ApplicationContext;
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.WebApplicationContext;
/**
* A handy opinionated {@link WebApplicationInitializer} for applications that starts a
* Spring Boot application and lets it bind to the servlet and filter mappings. If your
* application is more complicated consider using one of the other
* WebApplicationInitializers.
* <p>
* Note that a WebApplicationInitializer is only needed if you are building a war file and
* deploying it. If you prefer to run an embedded container (we do) then you won't need
* this at all.
*
* @author Dave Syer
*/
public abstract class SpringBootServletInitializer implements WebApplicationInitializer {
protected final Log logger = LogFactory.getLog(getClass());
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
WebApplicationContext rootAppContext = createRootApplicationContext(servletContext);
if (rootAppContext != null) {
servletContext.addListener(new ContextLoaderListener(rootAppContext) {
@Override
public void contextInitialized(ServletContextEvent event) {
// no-op because the application context is already initialized
}
});
}
else {
this.logger.debug("No ContextLoaderListener registered, as "
+ "createRootApplicationContext() did not "
+ "return an application context");
}
}
protected WebApplicationContext createRootApplicationContext(
ServletContext servletContext) {
ApplicationContext parent = null;
Object object = servletContext
.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
if (object instanceof ApplicationContext) {
this.logger.info("Root context already created (using as parent).");
parent = (ApplicationContext) object;
servletContext.setAttribute(
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, null);
}
SpringApplicationBuilder application = new SpringApplicationBuilder();
if (parent != null) {
application.initializers(new ParentContextApplicationContextInitializer(
parent));
}
application.initializers(new ServletContextApplicationContextInitializer(
servletContext));
application.contextClass(AnnotationConfigEmbeddedWebApplicationContext.class);
application = configure(application);
// Ensure error pages are registered
application.sources(ErrorPageFilter.class);
return (WebApplicationContext) application.run();
}
/**
* Configure the application. Normally all you would need to do it add sources (e.g.
* config classes) because other settings have sensible defaults. You might choose
* (for instance) to add default command line arguments, or set an active Spring
* profile.
* @param application a builder for the application context
* @see SpringApplicationBuilder
*/
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application;
}
}