beannameurlhandlermapping.java

一个关于Spring框架的示例应用程序,简单使用,可以参考.

/*
 * Copyright 2002-2004 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.handler;

import java.util.ArrayList;
import java.util.List;

import org.springframework.context.ApplicationContextException;

/**
 * Implementation of the HandlerMapping interface to map from URLs to beans with names
 * that start with a slash ("/"), similar to how Struts maps URLs to action names.
 * This is the default implementation used by the DispatcherServlet, but somewhat naive.
 * A SimpleUrlHandlerMapping or a custom handler mapping should be used by preference.
 *
 * <p>The mapping is from URL to bean name. Thus an incoming URL "/foo" would map
 * to a handler named "/foo", or to "/foo /foo2" in case of multiple mappings to
 * a single handler. Note: In XML definitions, you'll need to use an alias
 * name="/foo" in the bean definition, as the XML id may not contain slashes.
 *
 * <p>Supports direct matches (given "/test" -> registered "/test") and "*" matches
 * (given "/test" -> registered "/t*"). Note that the default is to map within the
 * current servlet mapping if applicable; see alwaysUseFullPath property for details.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see #setAlwaysUseFullPath
 * @see SimpleUrlHandlerMapping
 */
public class BeanNameUrlHandlerMapping extends AbstractUrlHandlerMapping {
	
	public void initApplicationContext() throws ApplicationContextException {
		if (logger.isDebugEnabled()) {
			logger.debug("Looking for URL mappings in application context: " + getApplicationContext());
		}
		String[] beanNames = getApplicationContext().getBeanDefinitionNames();

		// Take any bean name or alias that begins with a slash.
		for (int i = 0; i < beanNames.length; i++) {
			String[] urls = checkForUrl(beanNames[i]);
			if (urls.length > 0) {
				if (logger.isDebugEnabled()) {
					logger.debug("Found URL mapping [" + beanNames[i] + "]");
				}
				// Create a mapping to each part of the path.
				for (int j = 0; j < urls.length; j++) {
					registerHandler(urls[j], beanNames[i]);
				}
			}
			else {
				if (logger.isDebugEnabled()) {
					logger.debug("Rejected bean name '" + beanNames[i] + "'");
				}
			}
		}
	}

	/**
	 * Check name and aliases of the given bean for URLs,
	 * detected by starting with "/".
	 */
	protected String[] checkForUrl(String beanName) {
		List urls = new ArrayList();
		if (beanName.startsWith("/")) {
			urls.add(beanName);
		}
		String[] aliases = getApplicationContext().getAliases(beanName);
		for (int j = 0; j < aliases.length; j++) {
			if (aliases[j].startsWith("/")) {
				urls.add(aliases[j]);
			}
		}
		return (String[]) urls.toArray(new String[urls.size()]);
	}

}