Spring Framework example source code file (ClassPathResource.java)

This example Spring Framework source code file (ClassPathResource.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

class, classloader, classloader, classpathresource, classpathresource, file, filenotfoundexception, inputstream, io, ioexception, net, network, path, string, string, url, url

The Spring Framework ClassPathResource.java source code

/*
 * Copyright 2002-2008 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;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;

/**
 * {@link Resource} implementation for class path resources.
 * Uses either a given ClassLoader or a given Class for loading resources.
 *
 * <p>Supports resolution as java.io.File if the class path
 * resource resides in the file system, but not for resources in a JAR.
 * Always supports resolution as URL.
 *
 * @author Juergen Hoeller
 * @since 28.12.2003
 * @see java.lang.ClassLoader#getResourceAsStream(String)
 * @see java.lang.Class#getResourceAsStream(String)
 */
public class ClassPathResource extends AbstractResource {

	private final String path;

	private ClassLoader classLoader;

	private Class clazz;


	/**
	 * Create a new ClassPathResource for ClassLoader usage.
	 * A leading slash will be removed, as the ClassLoader
	 * resource access methods will not accept it.
	 * <p>The thread context class loader will be used for
	 * loading the resource.
	 * @param path the absolute path within the class path
	 * @see java.lang.ClassLoader#getResourceAsStream(String)
	 * @see org.springframework.util.ClassUtils#getDefaultClassLoader()
	 */
	public ClassPathResource(String path) {
		this(path, (ClassLoader) null);
	}

	/**
	 * Create a new ClassPathResource for ClassLoader usage.
	 * A leading slash will be removed, as the ClassLoader
	 * resource access methods will not accept it.
	 * @param path the absolute path within the classpath
	 * @param classLoader the class loader to load the resource with,
	 * or <code>null for the thread context class loader
	 * @see java.lang.ClassLoader#getResourceAsStream(String)
	 */
	public ClassPathResource(String path, ClassLoader classLoader) {
		Assert.notNull(path, "Path must not be null");
		if (path.startsWith("/")) {
			path = path.substring(1);
		}
		this.path = StringUtils.cleanPath(path);
		this.classLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());
	}

	/**
	 * Create a new ClassPathResource for Class usage.
	 * The path can be relative to the given class,
	 * or absolute within the classpath via a leading slash.
	 * @param path relative or absolute path within the class path
	 * @param clazz the class to load resources with
	 * @see java.lang.Class#getResourceAsStream
	 */
	public ClassPathResource(String path, Class clazz) {
		Assert.notNull(path, "Path must not be null");
		this.path = StringUtils.cleanPath(path);
		this.clazz = clazz;
	}

	/**
	 * Create a new ClassPathResource with optional ClassLoader and Class.
	 * Only for internal usage.
	 * @param path relative or absolute path within the classpath
	 * @param classLoader the class loader to load the resource with, if any
	 * @param clazz the class to load resources with, if any
	 */
	protected ClassPathResource(String path, ClassLoader classLoader, Class clazz) {
		this.path = path;
		this.classLoader = classLoader;
		this.clazz = clazz;
	}


	/**
	 * Return the path for this resource (as resource path within the class path).
	 */
	public final String getPath() {
		return this.path;
	}

	/**
	 * Return the ClassLoader that this resource will be obtained from.
	 */
	public final ClassLoader getClassLoader() {
		return (this.classLoader != null ? this.classLoader : this.clazz.getClassLoader());
	}


	/**
	 * This implementation opens an InputStream for the given class path resource.
	 * @see java.lang.ClassLoader#getResourceAsStream(String)
	 * @see java.lang.Class#getResourceAsStream(String)
	 */
	public InputStream getInputStream() throws IOException {
		InputStream is = null;
		if (this.clazz != null) {
			is = this.clazz.getResourceAsStream(this.path);
		}
		else {
			is = this.classLoader.getResourceAsStream(this.path);
		}
		if (is == null) {
			throw new FileNotFoundException(
					getDescription() + " cannot be opened because it does not exist");
		}
		return is;
	}

	/**
	 * This implementation returns a URL for the underlying class path resource.
	 * @see java.lang.ClassLoader#getResource(String)
	 * @see java.lang.Class#getResource(String)
	 */
	public URL getURL() throws IOException {
		URL url = null;
		if (this.clazz != null) {
			url = this.clazz.getResource(this.path);
		}
		else {
			url = this.classLoader.getResource(this.path);
		}
		if (url == null) {
			throw new FileNotFoundException(
					getDescription() + " cannot be resolved to URL because it does not exist");
		}
		return url;
	}

	/**
	 * This implementation returns a File reference for the underlying class path
	 * resource, provided that it refers to a file in the file system.
	 * @see org.springframework.util.ResourceUtils#getFile(java.net.URL, String)
	 */
	public File getFile() throws IOException {
		return ResourceUtils.getFile(getURL(), getDescription());
	}

	/**
	 * This implementation determines the underlying File
	 * (or jar file, in case of a resource in a jar/zip).
	 */
	protected File getFileForLastModifiedCheck() throws IOException {
		URL url = getURL();
		if (ResourceUtils.isJarURL(url)) {
			URL actualUrl = ResourceUtils.extractJarFileURL(url);
			return ResourceUtils.getFile(actualUrl);
		}
		else {
			return ResourceUtils.getFile(url, getDescription());
		}
	}

	/**
	 * This implementation creates a ClassPathResource, applying the given path
	 * relative to the path of the underlying resource of this descriptor.
	 * @see org.springframework.util.StringUtils#applyRelativePath(String, String)
	 */
	public Resource createRelative(String relativePath) {
		String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
		return new ClassPathResource(pathToUse, this.classLoader, this.clazz);
	}

	/**
	 * This implementation returns the name of the file that this class path
	 * resource refers to.
	 * @see org.springframework.util.StringUtils#getFilename(String)
	 */
	public String getFilename() {
		return StringUtils.getFilename(this.path);
	}

	/**
	 * This implementation returns a description that includes the class path location.
	 */
	public String getDescription() {
		return "class path resource [" + this.path + "]";
	}


	/**
	 * This implementation compares the underlying class path locations.
	 */
	public boolean equals(Object obj) {
		if (obj == this) {
			return true;
		}
		if (obj instanceof ClassPathResource) {
			ClassPathResource otherRes = (ClassPathResource) obj;
			return (this.path.equals(otherRes.path) &&
					ObjectUtils.nullSafeEquals(this.classLoader, otherRes.classLoader) &&
					ObjectUtils.nullSafeEquals(this.clazz, otherRes.clazz));
		}
		return false;
	}

	/**
	 * This implementation returns the hash code of the underlying
	 * class path location.
	 */
	public int hashCode() {
		return this.path.hashCode();
	}

}