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

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

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/*
 * Copyright 2002-2014 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.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;

/**
 * A simple {@code ResourceResolver} that tries to find a resource under the given
 * locations matching to the request path.
 *
 * <p>This resolver does not delegate to the {@code ResourceResolverChain} and is
 * expected to be configured at the end in a chain of resolvers.
 *
 * @author Jeremy Grelle
 * @author Rossen Stoyanchev
 * @author Sam Brannen
 * @since 4.1
 */
public class PathResourceResolver extends AbstractResourceResolver {

    @Override
    protected Resource resolveResourceInternal(HttpServletRequest request, String requestPath,
            List<? extends Resource> locations, ResourceResolverChain chain) {

        return getResource(requestPath, locations);
    }

    @Override
    protected String resolveUrlPathInternal(String resourceUrlPath, List<? extends Resource> locations,
            ResourceResolverChain chain) {

        return (getResource(resourceUrlPath, locations) != null ? resourceUrlPath : null);
    }

    private Resource getResource(String path, List<? extends Resource> locations) {
        for (Resource location : locations) {
            try {
                if (logger.isTraceEnabled()) {
                    logger.trace("Checking location=[" + location + "]");
                }
                Resource resource = location.createRelative(path);
                if (resource.exists() && resource.isReadable()) {
                    if (logger.isTraceEnabled()) {
                        logger.trace("Found match");
                    }
                    return resource;
                } else if (logger.isTraceEnabled()) {
                    logger.trace("No match");
                }
            } catch (IOException ex) {
                logger.trace("Failure checking for relative resource. Trying next location.", ex);
            }
        }
        return null;
    }

}