org.springframework.web.servlet.resource.PathExtensionResourceResolver.java Source code

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Here is the source code for org.springframework.web.servlet.resource.PathExtensionResourceResolver.java

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/*
 * Copyright 2002-2013 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.resource;

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.Resource;
import org.springframework.util.StringUtils;

/**
 *
 * @author Jeremy Grelle
 * @author Rossen Stoyanchev
 * @since 4.0
 */
public class PathExtensionResourceResolver implements ResourceResolver {

    private static final Log logger = LogFactory.getLog(PathExtensionResourceResolver.class);

    private final boolean compareTimeStamp;

    public PathExtensionResourceResolver() {
        this.compareTimeStamp = false;
    }

    public PathExtensionResourceResolver(boolean compareTimeStamp) {
        this.compareTimeStamp = compareTimeStamp;
    }

    @Override
    public Resource resolveResource(HttpServletRequest request, String requestPath, List<Resource> locations,
            ResourceResolverChain chain) {

        Resource resource = chain.resolveResource(request, requestPath, locations);
        if ((resource != null) && !this.compareTimeStamp) {
            return resource;
        }

        for (Resource location : locations) {
            String baseFilename = StringUtils.getFilename(requestPath);
            try {
                Resource basePath = location.createRelative(StringUtils.delete(requestPath, baseFilename));
                if (basePath.getFile().isDirectory()) {
                    for (String fileName : basePath.getFile().list(new ExtensionFilenameFilter(baseFilename))) {
                        //Always use the first match
                        Resource matched = basePath.createRelative(fileName);
                        if ((resource == null) || (matched.lastModified() > resource.lastModified())) {
                            return matched;
                        } else {
                            return resource;
                        }
                    }
                }
            } catch (IOException e) {
                logger.trace("Error occurred locating resource based on file extension mapping", e);
            }
        }

        return resource;
    }

    @Override
    public String resolveUrlPath(String resourcePath, List<Resource> locations, ResourceResolverChain chain) {

        String resolved = chain.resolveUrlPath(resourcePath, locations);
        if (StringUtils.hasText(resolved)) {
            return resolved;
        }

        Resource mappedResource = resolveResource(null, resourcePath, locations, chain);
        if (mappedResource != null) {
            return resourcePath;
        }
        return null;
    }

    private static final class ExtensionFilenameFilter implements FilenameFilter {

        private final String filename;

        private final String extension;

        private final int extensionLength;

        public ExtensionFilenameFilter(String filename) {
            this.filename = filename;
            this.extension = "." + StringUtils.getFilenameExtension(filename);
            this.extensionLength = this.extension.length();
        }

        @Override
        public boolean accept(File directory, String name) {
            return (name.contains(this.extension) && this.filename
                    .equals(name.substring(0, name.lastIndexOf(this.extension) + this.extensionLength)));
        }
    }

}