1 /* 2 * Copyright 2002-2011 the original author or authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.springframework.web.servlet.config.annotation; 18 19 import java.util.HashMap; 20 import java.util.Map; 21 22 import javax.servlet.ServletContext; 23 24 import org.springframework.util.Assert; 25 import org.springframework.web.HttpRequestHandler; 26 import org.springframework.web.servlet.DispatcherServlet; 27 import org.springframework.web.servlet.handler.AbstractHandlerMapping; 28 import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping; 29 import org.springframework.web.servlet.resource.DefaultServletHttpRequestHandler; 30 31 /** 32 * Configures a request handler for serving static resources by forwarding the request to the Servlet container's 33 * "default" Servlet. This is indended to be used when the Spring MVC {@link DispatcherServlet} is mapped to "/" 34 * thus overriding the Servlet container's default handling of static resources. Since this handler is configured 35 * at the lowest precedence, effectively it allows all other handler mappings to handle the request, and if none 36 * of them do, this handler can forward it to the "default" Servlet. 37 * 38 * @author Rossen Stoyanchev 39 * @since 3.1 40 * 41 * @see DefaultServletHttpRequestHandler 42 */ 43 public class DefaultServletHandlerConfigurer { 44 45 private final ServletContext servletContext; 46 47 private DefaultServletHttpRequestHandler handler; 48 49 /** 50 * Create a {@link DefaultServletHandlerConfigurer} instance. 51 * @param servletContext the ServletContext to use to configure the underlying DefaultServletHttpRequestHandler. 52 */ DefaultServletHandlerConfigurer(ServletContext servletContext)53 public DefaultServletHandlerConfigurer(ServletContext servletContext) { 54 Assert.notNull(servletContext, "A ServletContext is required to configure default servlet handling"); 55 this.servletContext = servletContext; 56 } 57 58 /** 59 * Enable forwarding to the "default" Servlet. When this method is used the {@link DefaultServletHttpRequestHandler} 60 * will try to auto-detect the "default" Servlet name. Alternatively, you can specify the name of the default 61 * Servlet via {@link #enable(String)}. 62 * @see DefaultServletHttpRequestHandler 63 */ enable()64 public void enable() { 65 enable(null); 66 } 67 68 /** 69 * Enable forwarding to the "default" Servlet identified by the given name. 70 * This is useful when the default Servlet cannot be auto-detected, for example when it has been manually configured. 71 * @see DefaultServletHttpRequestHandler 72 */ enable(String defaultServletName)73 public void enable(String defaultServletName) { 74 handler = new DefaultServletHttpRequestHandler(); 75 handler.setDefaultServletName(defaultServletName); 76 handler.setServletContext(servletContext); 77 } 78 79 /** 80 * Return a handler mapping instance ordered at {@link Integer#MAX_VALUE} containing the 81 * {@link DefaultServletHttpRequestHandler} instance mapped to {@code "/**"}; or {@code null} if 82 * default servlet handling was not been enabled. 83 */ getHandlerMapping()84 protected AbstractHandlerMapping getHandlerMapping() { 85 if (handler == null) { 86 return null; 87 } 88 89 Map<String, HttpRequestHandler> urlMap = new HashMap<String, HttpRequestHandler>(); 90 urlMap.put("/**", handler); 91 92 SimpleUrlHandlerMapping handlerMapping = new SimpleUrlHandlerMapping(); 93 handlerMapping.setOrder(Integer.MAX_VALUE); 94 handlerMapping.setUrlMap(urlMap); 95 return handlerMapping; 96 } 97 98 }