https://github.com/spring-projects/spring-framework: Spring Web (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 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.context.support;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import javax.servlet.ServletContext;

import org.springframework.core.io.AbstractFileResolvingResource;
import org.springframework.core.io.ContextResource;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.util.WebUtils;


Resource implementation for ServletContext resources, interpreting relative paths within the web application root directory. 
Always supports stream access and URL access, but only allows java.io.File access when the web application archive is expanded. 
Author:Juergen Hoeller
See Also:
Since:28.12.2003
/**
 * {@link org.springframework.core.io.Resource} implementation for
 * {@link javax.servlet.ServletContext} resources, interpreting
 * relative paths within the web application root directory.
 *
 * <p>Always supports stream access and URL access, but only allows
 * {@code java.io.File} access when the web application archive
 * is expanded.
 *
 * @author Juergen Hoeller
 * @since 28.12.2003
 * @see javax.servlet.ServletContext#getResourceAsStream
 * @see javax.servlet.ServletContext#getResource
 * @see javax.servlet.ServletContext#getRealPath
 */
public class ServletContextResource extends AbstractFileResolvingResource implements ContextResource {

	private final ServletContext servletContext;

	private final String path;


	
Create a new ServletContextResource.

The Servlet spec requires that resource paths start with a slash,
even if many containers accept paths without leading slash too.
Consequently, the given path will be prepended with a slash if it
doesn't already start with one.

Params:
  • servletContext – the ServletContext to load from
  • path – the path of the resource
/**
	 * Create a new ServletContextResource.
	 * <p>The Servlet spec requires that resource paths start with a slash,
	 * even if many containers accept paths without leading slash too.
	 * Consequently, the given path will be prepended with a slash if it
	 * doesn't already start with one.
	 * @param servletContext the ServletContext to load from
	 * @param path the path of the resource
	 */
	public ServletContextResource(ServletContext servletContext, String path) {
		// check ServletContext
		Assert.notNull(servletContext, "Cannot resolve ServletContextResource without ServletContext");
		this.servletContext = servletContext;

		// check path
		Assert.notNull(path, "Path is required");
		String pathToUse = StringUtils.cleanPath(path);
		if (!pathToUse.startsWith("/")) {
			pathToUse = "/" + pathToUse;
		}
		this.path = pathToUse;
	}


	
Return the ServletContext for this resource.

/**
	 * Return the ServletContext for this resource.
	 */
	public final ServletContext getServletContext() {
		return this.servletContext;
	}

	
Return the path for this resource.

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

	
This implementation checks ServletContext.getResource. 
See Also:
/**
	 * This implementation checks {@code ServletContext.getResource}.
	 * @see javax.servlet.ServletContext#getResource(String)
	 */
	@Override
	public boolean exists() {
		try {
			URL url = this.servletContext.getResource(this.path);
			return (url != null);
		}
		catch (MalformedURLException ex) {
			return false;
		}
	}

	
This implementation delegates to ServletContext.getResourceAsStream, which returns null in case of a non-readable resource (e.g. a directory). 
See Also:
/**
	 * This implementation delegates to {@code ServletContext.getResourceAsStream},
	 * which returns {@code null} in case of a non-readable resource (e.g. a directory).
	 * @see javax.servlet.ServletContext#getResourceAsStream(String)
	 */
	@Override
	public boolean isReadable() {
		InputStream is = this.servletContext.getResourceAsStream(this.path);
		if (is != null) {
			try {
				is.close();
			}
			catch (IOException ex) {
				// ignore
			}
			return true;
		}
		else {
			return false;
		}
	}

	@Override
	public boolean isFile() {
		try {
			URL url = this.servletContext.getResource(this.path);
			if (url != null && ResourceUtils.isFileURL(url)) {
				return true;
			}
			else {
				return (this.servletContext.getRealPath(this.path) != null);
			}
		}
		catch (MalformedURLException ex) {
			return false;
		}
	}

	
This implementation delegates to ServletContext.getResourceAsStream, but throws a FileNotFoundException if no resource found. 
See Also:
/**
	 * This implementation delegates to {@code ServletContext.getResourceAsStream},
	 * but throws a FileNotFoundException if no resource found.
	 * @see javax.servlet.ServletContext#getResourceAsStream(String)
	 */
	@Override
	public InputStream getInputStream() throws IOException {
		InputStream is = this.servletContext.getResourceAsStream(this.path);
		if (is == null) {
			throw new FileNotFoundException("Could not open " + getDescription());
		}
		return is;
	}

	
This implementation delegates to ServletContext.getResource, but throws a FileNotFoundException if no resource found. 
See Also:
/**
	 * This implementation delegates to {@code ServletContext.getResource},
	 * but throws a FileNotFoundException if no resource found.
	 * @see javax.servlet.ServletContext#getResource(String)
	 */
	@Override
	public URL getURL() throws IOException {
		URL url = this.servletContext.getResource(this.path);
		if (url == null) {
			throw new FileNotFoundException(
					getDescription() + " cannot be resolved to URL because it does not exist");
		}
		return url;
	}

	
This implementation resolves "file:" URLs or alternatively delegates to ServletContext.getRealPath, throwing a FileNotFoundException if not found or not resolvable. 
See Also:
/**
	 * This implementation resolves "file:" URLs or alternatively delegates to
	 * {@code ServletContext.getRealPath}, throwing a FileNotFoundException
	 * if not found or not resolvable.
	 * @see javax.servlet.ServletContext#getResource(String)
	 * @see javax.servlet.ServletContext#getRealPath(String)
	 */
	@Override
	public File getFile() throws IOException {
		URL url = this.servletContext.getResource(this.path);
		if (url != null && ResourceUtils.isFileURL(url)) {
			// Proceed with file system resolution...
			return super.getFile();
		}
		else {
			String realPath = WebUtils.getRealPath(this.servletContext, this.path);
			return new File(realPath);
		}
	}

	
This implementation creates a ServletContextResource, applying the given path
relative to the path of the underlying file of this resource descriptor.

See Also:
  • applyRelativePath.applyRelativePath(String, String)
/**
	 * This implementation creates a ServletContextResource, applying the given path
	 * relative to the path of the underlying file of this resource descriptor.
	 * @see org.springframework.util.StringUtils#applyRelativePath(String, String)
	 */
	@Override
	public Resource createRelative(String relativePath) {
		String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
		return new ServletContextResource(this.servletContext, pathToUse);
	}

	
This implementation returns the name of the file that this ServletContext
resource refers to.

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

	
This implementation returns a description that includes the ServletContext
resource location.

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

	@Override
	public String getPathWithinContext() {
		return this.path;
	}


	
This implementation compares the underlying ServletContext resource locations.

/**
	 * This implementation compares the underlying ServletContext resource locations.
	 */
	@Override
	public boolean equals(Object other) {
		if (this == other) {
			return true;
		}
		if (!(other instanceof ServletContextResource)) {
			return false;
		}
		ServletContextResource otherRes = (ServletContextResource) other;
		return (this.servletContext.equals(otherRes.servletContext) && this.path.equals(otherRes.path));
	}

	
This implementation returns the hash code of the underlying
ServletContext resource location.

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

}