/*
* Copyright 2002-2011 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.servlet.config.annotation;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletContext;
import org.springframework.util.Assert;
import org.springframework.web.HttpRequestHandler;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.handler.AbstractHandlerMapping;
import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping;
import org.springframework.web.servlet.resource.DefaultServletHttpRequestHandler;
/**
* Configures a request handler for serving static resources by forwarding the request to the Servlet container's
* "default" Servlet. This is intended to be used when the Spring MVC {@link DispatcherServlet} is mapped to "/"
* thus overriding the Servlet container's default handling of static resources. Since this handler is configured
* at the lowest precedence, effectively it allows all other handler mappings to handle the request, and if none
* of them do, this handler can forward it to the "default" Servlet.
*
* @author Rossen Stoyanchev
* @since 3.1
*
* @see DefaultServletHttpRequestHandler
*/
public class DefaultServletHandlerConfigurer {
private final ServletContext servletContext;
private DefaultServletHttpRequestHandler handler;
/**
* Create a {@link DefaultServletHandlerConfigurer} instance.
* @param servletContext the ServletContext to use to configure the underlying DefaultServletHttpRequestHandler.
*/
public DefaultServletHandlerConfigurer(ServletContext servletContext) {
Assert.notNull(servletContext, "A ServletContext is required to configure default servlet handling");
this.servletContext = servletContext;
}
/**
* Enable forwarding to the "default" Servlet. When this method is used the {@link DefaultServletHttpRequestHandler}
* will try to auto-detect the "default" Servlet name. Alternatively, you can specify the name of the default
* Servlet via {@link #enable(String)}.
* @see DefaultServletHttpRequestHandler
*/
public void enable() {
enable(null);
}
/**
* Enable forwarding to the "default" Servlet identified by the given name.
* This is useful when the default Servlet cannot be auto-detected, for example when it has been manually configured.
* @see DefaultServletHttpRequestHandler
*/
public void enable(String defaultServletName) {
handler = new DefaultServletHttpRequestHandler();
handler.setDefaultServletName(defaultServletName);
handler.setServletContext(servletContext);
}
/**
* Return a handler mapping instance ordered at {@link Integer#MAX_VALUE} containing the
* {@link DefaultServletHttpRequestHandler} instance mapped to {@code "/**"}; or {@code null} if
* default servlet handling was not been enabled.
*/
protected AbstractHandlerMapping getHandlerMapping() {
if (handler == null) {
return null;
}
Map<String, HttpRequestHandler> urlMap = new HashMap<String, HttpRequestHandler>();
urlMap.put("/**", handler);
SimpleUrlHandlerMapping handlerMapping = new SimpleUrlHandlerMapping();
handlerMapping.setOrder(Integer.MAX_VALUE);
handlerMapping.setUrlMap(urlMap);
return handlerMapping;
}
}