pathmatchingresourcepatternresolver.java

spring api 源代码

/*
 * 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.core.io.support;

import java.io.File;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.core.CollectionFactory;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.UrlResource;
import org.springframework.util.AntPathMatcher;
import org.springframework.util.Assert;
import org.springframework.util.PathMatcher;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;

/**
 * A {@link ResourcePatternResolver} implementation that is able to resolve a
 * specified resource location path into one or more matching Resources.
 * The source path may be a simple path which has a one-to-one mapping to a
 * target {@link org.springframework.core.io.Resource}, or alternatively
 * may contain the special "<code>classpath*:</code>" prefix and/or
 * internal Ant-style regular expressions (matched using Spring's
 * {@link org.springframework.util.AntPathMatcher} utility).
 * Both of the latter are effectively wildcards.
 *
 * <p><b>No Wildcards:</b>
 *
 * <p>In the simple case, if the specified location path does not start with the
 * <code>"classpath*:</code>" prefix, and does not contain a PathMatcher pattern,
 * this resolver will simply return a single resource via a
 * <code>getResource()</code> call on the underlying <code>ResourceLoader</code>.
 * Examples are real URLs such as "<code>file:C:/context.xml</code>", pseudo-URLs
 * such as "<code>classpath:/context.xml</code>", and simple unprefixed paths
 * such as "<code>/WEB-INF/context.xml</code>". The latter will resolve in a
 * fashion specific to the underlaying <code>ResourceLoader</code> (e.g. 
 * <code>ServletContextResource</code> for a <code>WebApplicationContext</code>).
 *
 * <p><b>Ant-style Patterns:</b>
 *
 * <p>When the path location contains an Ant-style pattern, e.g.:
 * <pre>
 * /WEB-INF/*-context.xml
 * com/mycompany/**&#47;applicationContext.xml
 * file:C:/some/path/*-context.xml
 * classpath:com/mycompany/**&#47;applicationContext.xml</pre>
 * the resolver follows a more complex but defined procedure to try to resolve
 * the wildcard. It produces a <code>Resource</code> for the path up to the last
 * non-wildcard segment and obtains a <code>URL</code> from it. If this URL is
 * not a "<code>jar:</code>" URL or container-specific variant (e.g.
 * "<code>zip:</code>" in WebLogic, "<code>wsjar</code>" in WebSphere", etc.),
 * then a <code>java.io.File</code> is obtained from it, and used to resolve the
 * wildcard by walking the filesystem. In the case of a jar URL, the resolver
 * either gets a <code>java.net.JarURLConnection</code> from it, or manually parse
 * the jar URL, and then traverse the contents of the jar file, to resolve the
 * wildcards.
 *
 * <p><b>Implications on portability:</b>
 *
 * <p>If the specified path is already a file URL (either explicitly, or
 * implicitly because the base <code>ResourceLoader</code> is a filesystem one,
 * then wildcarding is guaranteed to work in a completely poratable fashion.
 *
 * <p>If the specified path is a classpath location, then the resolver must
 * obtain the last non-wildcard path segment URL via a
 * <code>Classloader.getResource()</code> call. Since this is just a
 * node of the path (not the file at the end) it is actually undefined
 * (in the ClassLoader Javadocs) exactly what sort of a URL is returned in
 * this case. In practice, it is usually a <code>java.io.File</code> representing
 * the directory, where the classpath resource resolves to a filesystem
 * location, or a jar URL of some sort, where the classpath resource resolves
 * to a jar location. Still, there is a portability concern on this operation.
 *
 * <p>If a jar URL is obtained for the last non-wildcard segment, the resolver
 * must be able to get a <code>java.net.JarURLConnection</code> from it, or
 * manually parse the jar URL, to be able to walk the contents of the jar,
 * and resolve the wildcard. This will work in most environments, but will
 * fail in others, and it is strongly recommended that the wildcard
 * resolution of resources coming from jars be thoroughly tested in your
 * specific environment before you rely on it.
 *
 * <p><b><code>classpath*:</code> Prefix:</b>
 *
 * <p>There is special support for retrieving multiple class path resources with
 * the same name, via the "<code>classpath*:</code>" prefix. For example,
 * "<code>classpath*:META-INF/beans.xml</code>" will find all "beans.xml"
 * files in the class path, be it in "classes" directories or in JAR files.
 * This is particularly useful for autodetecting config files of the same name
 * at the same location within each jar file. Internally, this happens via a
 * <code>ClassLoader.getResources()</code> call, and is completely portable.
 *
 * <p>The "classpath*:" prefix can also be combined with a PathMatcher pattern in
 * the rest of the location path, for example "classpath*:META-INF/*-beans.xml".
 * In this case, the resolution strategy is fairly simple: a
 * <code>ClassLoader.getResources()</code> call is used on the last non-wildcard
 * path segment to get all the matching resources in the class loader hierarchy,
 * and then off each resource the same PathMatcher resoltion strategy described
 * above is used for the wildcard subpath.
 *
 * <p><b>Other notes:</b>
 *
 * <p><b>WARNING:</b> Note that "<code>classpath*:</code>" when combined with
 * Ant-style patterns will only work reliably with at least one root directory
 * before the pattern starts, unless the actual target files reside in the file
 * system. This means that a pattern like "<code>classpath*:*.xml</code>" will
 * <i>not</i> retrieve files from the root of jar files but rather only from the
 * root of expanded directories. This originates from a limitation in the JDK's
 * <code>ClassLoader.getResources()</code> method which only returns file system
 * locations for a passed-in empty String (indicating potential roots to search).
 *
 * <p><b>WARNING:</b> Ant-style patterns with "classpath:" resources are not
 * guaranteed to find matching resources if the root package to search is available
 * in multiple class path locations. This is because a resource such as<pre>
 *     com/mycompany/package1/service-context.xml
 * </pre>may be in only one location, but when a path such as<pre>
 *     classpath:com/mycompany/**&#47;service-context.xml
 * </pre>is used to try to resolve it, the resolver will work off the (first) URL 
 * returned by <code>getResource("com/mycompany");</code>. If this base package
 * node exists in multiple classloader locations, the actual end resource may
 * not be underneath. Therefore, preferably, use "<code>classpath*:<code>" with the same
 * Ant-style pattern in such a case, which will search <i>all</i> class path
 * locations that contain the root package.
 *
 * @author Juergen Hoeller
 * @author Colin Sampaleanu
 * @since 1.0.2
 * @see #CLASSPATH_ALL_URL_PREFIX
 * @see org.springframework.util.AntPathMatcher
 * @see org.springframework.core.io.ResourceLoader#getResource(String)
 * @see java.lang.ClassLoader#getResources(String)
 */
public class PathMatchingResourcePatternResolver implements ResourcePatternResolver {

	protected static final Log logger = LogFactory.getLog(PathMatchingResourcePatternResolver.class);

	private final ResourceLoader resourceLoader;

	private PathMatcher pathMatcher = new AntPathMatcher();


	/**
	 * Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader.
	 * <p>ClassLoader access will happen via the thread context class loader.
	 * @see org.springframework.core.io.DefaultResourceLoader
	 */
	public PathMatchingResourcePatternResolver() {
		this.resourceLoader = new DefaultResourceLoader();
	}

	/**
	 * Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader.
	 * @param classLoader the ClassLoader to load classpath resources with,
	 * or <code>null</code> for using the thread context class loader
	 * @see org.springframework.core.io.DefaultResourceLoader
	 */
	public PathMatchingResourcePatternResolver(ClassLoader classLoader) {
		this.resourceLoader = new DefaultResourceLoader(classLoader);
	}

	/**
	 * Create a new PathMatchingResourcePatternResolver.
	 * <p>ClassLoader access will happen via the thread context class loader.
	 * @param resourceLoader the ResourceLoader to load root directories and
	 * actual resources with
	 */
	public PathMatchingResourcePatternResolver(ResourceLoader resourceLoader) {
		Assert.notNull(resourceLoader, "ResourceLoader must not be null");
		this.resourceLoader = resourceLoader;
	}


	/**
	 * Return the ResourceLoader that this pattern resolver works with.
	 */
	public ResourceLoader getResourceLoader() {
		return this.resourceLoader;
	}

	/**
	 * Return the ClassLoader that this pattern resolver works with
	 * (never <code>null</code>).
	 */
	public ClassLoader getClassLoader() {
		return getResourceLoader().getClassLoader();
	}

	/**
	 * Set the PathMatcher implementation to use for this
	 * resource pattern resolver. Default is AntPathMatcher.
	 * @see org.springframework.util.AntPathMatcher
	 */
	public void setPathMatcher(PathMatcher pathMatcher) {
		Assert.notNull(pathMatcher, "PathMatcher must not be null");
		this.pathMatcher = pathMatcher;
	}

	/**
	 * Return the PathMatcher that this resource pattern resolver uses.
	 */
	public PathMatcher getPathMatcher() {
		return this.pathMatcher;
	}


	public Resource getResource(String location) {
		return getResourceLoader().getResource(location);
	}

	public Resource[] getResources(String locationPattern) throws IOException {
		Assert.notNull(locationPattern, "Location pattern must not be null");
		if (locationPattern.startsWith(CLASSPATH_ALL_URL_PREFIX)) {
			// a class path resource (multiple resources for same name possible)
			if (getPathMatcher().isPattern(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length()))) {
				// a class path resource pattern
				return findPathMatchingResources(locationPattern);
			}
			else {
				// all class path resources with the given name
				return findAllClassPathResources(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length()));
			}
		}
		else {
			// Only look for a pattern after a prefix here
			// (to not get fooled by a pattern symbol in a strange prefix).
			int prefixEnd = locationPattern.indexOf(":") + 1;
			if (getPathMatcher().isPattern(locationPattern.substring(prefixEnd))) {
				// a file pattern
				return findPathMatchingResources(locationPattern);
			}
			else {
				// a single resource with the given name
				return new Resource[] {getResourceLoader().getResource(locationPattern)};
			}
		}
	}


	/**
	 * Find all class location resources with the given location via the ClassLoader.
	 * @param location the absolute path within the classpath
	 * @return the result as Resource array
	 * @throws IOException in case of I/O errors
	 * @see java.lang.ClassLoader#getResources
	 * @see #convertClassLoaderURL
	 */