org.springframework.util.ResourceUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2023 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
*
* https://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.util;
import java.io.File;
import java.io.FileNotFoundException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import org.springframework.lang.Nullable;
/**
* Utility methods for resolving resource locations to files in the
* file system. Mainly for internal use within the framework.
*
* Consider using Spring's Resource abstraction in the core package
* for handling all kinds of file resources in a uniform manner.
* {@link org.springframework.core.io.ResourceLoader}'s {@code getResource()}
* method can resolve any location to a {@link org.springframework.core.io.Resource}
* object, which in turn allows one to obtain a {@code java.io.File} in the
* file system through its {@code getFile()} method.
*
* @author Juergen Hoeller
* @since 1.1.5
* @see org.springframework.core.io.Resource
* @see org.springframework.core.io.ClassPathResource
* @see org.springframework.core.io.FileSystemResource
* @see org.springframework.core.io.UrlResource
* @see org.springframework.core.io.ResourceLoader
*/
public abstract class ResourceUtils {
/** Pseudo URL prefix for loading from the class path: "classpath:". */
public static final String CLASSPATH_URL_PREFIX = "classpath:";
/** URL prefix for loading from the file system: "file:". */
public static final String FILE_URL_PREFIX = "file:";
/** URL prefix for loading from a jar file: "jar:". */
public static final String JAR_URL_PREFIX = "jar:";
/** URL prefix for loading from a war file on Tomcat: "war:". */
public static final String WAR_URL_PREFIX = "war:";
/** URL protocol for a file in the file system: "file". */
public static final String URL_PROTOCOL_FILE = "file";
/** URL protocol for an entry from a jar file: "jar". */
public static final String URL_PROTOCOL_JAR = "jar";
/** URL protocol for an entry from a war file: "war". */
public static final String URL_PROTOCOL_WAR = "war";
/** URL protocol for an entry from a zip file: "zip". */
public static final String URL_PROTOCOL_ZIP = "zip";
/** URL protocol for an entry from a WebSphere jar file: "wsjar". */
public static final String URL_PROTOCOL_WSJAR = "wsjar";
/** URL protocol for an entry from a JBoss jar file: "vfszip". */
public static final String URL_PROTOCOL_VFSZIP = "vfszip";
/** URL protocol for a JBoss file system resource: "vfsfile". */
public static final String URL_PROTOCOL_VFSFILE = "vfsfile";
/** URL protocol for a general JBoss VFS resource: "vfs". */
public static final String URL_PROTOCOL_VFS = "vfs";
/** File extension for a regular jar file: ".jar". */
public static final String JAR_FILE_EXTENSION = ".jar";
/** Separator between JAR URL and file path within the JAR: "!/". */
public static final String JAR_URL_SEPARATOR = "!/";
/** Special separator between WAR URL and jar part on Tomcat. */
public static final String WAR_URL_SEPARATOR = "*/";
/**
* Return whether the given resource location is a URL:
* either a special "classpath" pseudo URL or a standard URL.
* @param resourceLocation the location String to check
* @return whether the location qualifies as a URL
* @see #CLASSPATH_URL_PREFIX
* @see java.net.URL
*/
public static boolean isUrl(@Nullable String resourceLocation) {
if (resourceLocation == null) {
return false;
}
if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
return true;
}
try {
toURL(resourceLocation);
return true;
}
catch (MalformedURLException ex) {
return false;
}
}
/**
* Resolve the given resource location to a {@code java.net.URL}.
*
Does not check whether the URL actually exists; simply returns
* the URL that the given location would correspond to.
* @param resourceLocation the resource location to resolve: either a
* "classpath:" pseudo URL, a "file:" URL, or a plain file path
* @return a corresponding URL object
* @throws FileNotFoundException if the resource cannot be resolved to a URL
*/
public static URL getURL(String resourceLocation) throws FileNotFoundException {
Assert.notNull(resourceLocation, "Resource location must not be null");
if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
String path = resourceLocation.substring(CLASSPATH_URL_PREFIX.length());
ClassLoader cl = ClassUtils.getDefaultClassLoader();
URL url = (cl != null ? cl.getResource(path) : ClassLoader.getSystemResource(path));
if (url == null) {
String description = "class path resource [" + path + "]";
throw new FileNotFoundException(description +
" cannot be resolved to URL because it does not exist");
}
return url;
}
try {
// try URL
return toURL(resourceLocation);
}
catch (MalformedURLException ex) {
// no URL -> treat as file path
try {
return new File(resourceLocation).toURI().toURL();
}
catch (MalformedURLException ex2) {
throw new FileNotFoundException("Resource location [" + resourceLocation +
"] is neither a URL not a well-formed file path");
}
}
}
/**
* Resolve the given resource location to a {@code java.io.File},
* i.e. to a file in the file system.
*
Does not check whether the file actually exists; simply returns
* the File that the given location would correspond to.
* @param resourceLocation the resource location to resolve: either a
* "classpath:" pseudo URL, a "file:" URL, or a plain file path
* @return a corresponding File object
* @throws FileNotFoundException if the resource cannot be resolved to
* a file in the file system
*/
public static File getFile(String resourceLocation) throws FileNotFoundException {
Assert.notNull(resourceLocation, "Resource location must not be null");
if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
String path = resourceLocation.substring(CLASSPATH_URL_PREFIX.length());
String description = "class path resource [" + path + "]";
ClassLoader cl = ClassUtils.getDefaultClassLoader();
URL url = (cl != null ? cl.getResource(path) : ClassLoader.getSystemResource(path));
if (url == null) {
throw new FileNotFoundException(description +
" cannot be resolved to absolute file path because it does not exist");
}
return getFile(url, description);
}
try {
// try URL
return getFile(toURL(resourceLocation));
}
catch (MalformedURLException ex) {
// no URL -> treat as file path
return new File(resourceLocation);
}
}
/**
* Resolve the given resource URL to a {@code java.io.File},
* i.e. to a file in the file system.
* @param resourceUrl the resource URL to resolve
* @return a corresponding File object
* @throws FileNotFoundException if the URL cannot be resolved to
* a file in the file system
*/
public static File getFile(URL resourceUrl) throws FileNotFoundException {
return getFile(resourceUrl, "URL");
}
/**
* Resolve the given resource URL to a {@code java.io.File},
* i.e. to a file in the file system.
* @param resourceUrl the resource URL to resolve
* @param description a description of the original resource that
* the URL was created for (for example, a class path location)
* @return a corresponding File object
* @throws FileNotFoundException if the URL cannot be resolved to
* a file in the file system
*/
public static File getFile(URL resourceUrl, String description) throws FileNotFoundException {
Assert.notNull(resourceUrl, "Resource URL must not be null");
if (!URL_PROTOCOL_FILE.equals(resourceUrl.getProtocol())) {
throw new FileNotFoundException(
description + " cannot be resolved to absolute file path " +
"because it does not reside in the file system: " + resourceUrl);
}
try {
// URI decoding for special characters such as spaces.
return new File(toURI(resourceUrl).getSchemeSpecificPart());
}
catch (URISyntaxException ex) {
// Fallback for URLs that are not valid URIs (should hardly ever happen).
return new File(resourceUrl.getFile());
}
}
/**
* Resolve the given resource URI to a {@code java.io.File},
* i.e. to a file in the file system.
* @param resourceUri the resource URI to resolve
* @return a corresponding File object
* @throws FileNotFoundException if the URL cannot be resolved to
* a file in the file system
* @since 2.5
*/
public static File getFile(URI resourceUri) throws FileNotFoundException {
return getFile(resourceUri, "URI");
}
/**
* Resolve the given resource URI to a {@code java.io.File},
* i.e. to a file in the file system.
* @param resourceUri the resource URI to resolve
* @param description a description of the original resource that
* the URI was created for (for example, a class path location)
* @return a corresponding File object
* @throws FileNotFoundException if the URL cannot be resolved to
* a file in the file system
* @since 2.5
*/
public static File getFile(URI resourceUri, String description) throws FileNotFoundException {
Assert.notNull(resourceUri, "Resource URI must not be null");
if (!URL_PROTOCOL_FILE.equals(resourceUri.getScheme())) {
throw new FileNotFoundException(
description + " cannot be resolved to absolute file path " +
"because it does not reside in the file system: " + resourceUri);
}
return new File(resourceUri.getSchemeSpecificPart());
}
/**
* Determine whether the given URL points to a resource in the file system,
* i.e. has protocol "file", "vfsfile" or "vfs".
* @param url the URL to check
* @return whether the URL has been identified as a file system URL
*/
public static boolean isFileURL(URL url) {
String protocol = url.getProtocol();
return (URL_PROTOCOL_FILE.equals(protocol) || URL_PROTOCOL_VFSFILE.equals(protocol) ||
URL_PROTOCOL_VFS.equals(protocol));
}
/**
* Determine whether the given URL points to a resource in a jar file.
* i.e. has protocol "jar", "war, ""zip", "vfszip" or "wsjar".
* @param url the URL to check
* @return whether the URL has been identified as a JAR URL
*/
public static boolean isJarURL(URL url) {
String protocol = url.getProtocol();
return (URL_PROTOCOL_JAR.equals(protocol) || URL_PROTOCOL_WAR.equals(protocol) ||
URL_PROTOCOL_ZIP.equals(protocol) || URL_PROTOCOL_VFSZIP.equals(protocol) ||
URL_PROTOCOL_WSJAR.equals(protocol));
}
/**
* Determine whether the given URL points to a jar file itself,
* that is, has protocol "file" and ends with the ".jar" extension.
* @param url the URL to check
* @return whether the URL has been identified as a JAR file URL
* @since 4.1
*/
public static boolean isJarFileURL(URL url) {
return (URL_PROTOCOL_FILE.equals(url.getProtocol()) &&
url.getPath().toLowerCase().endsWith(JAR_FILE_EXTENSION));
}
/**
* Extract the URL for the actual jar file from the given URL
* (which may point to a resource in a jar file or to a jar file itself).
* @param jarUrl the original URL
* @return the URL for the actual jar file
* @throws MalformedURLException if no valid jar file URL could be extracted
*/
public static URL extractJarFileURL(URL jarUrl) throws MalformedURLException {
String urlFile = jarUrl.getFile();
int separatorIndex = urlFile.indexOf(JAR_URL_SEPARATOR);
if (separatorIndex != -1) {
String jarFile = urlFile.substring(0, separatorIndex);
try {
return toURL(jarFile);
}
catch (MalformedURLException ex) {
// Probably no protocol in original jar URL, like "jar:C:/mypath/myjar.jar".
// This usually indicates that the jar file resides in the file system.
if (!jarFile.startsWith("/")) {
jarFile = "/" + jarFile;
}
return toURL(FILE_URL_PREFIX + jarFile);
}
}
else {
return jarUrl;
}
}
/**
* Extract the URL for the outermost archive from the given jar/war URL
* (which may point to a resource in a jar file or to a jar file itself).
*
In the case of a jar file nested within a war file, this will return
* a URL to the war file since that is the one resolvable in the file system.
* @param jarUrl the original URL
* @return the URL for the actual jar file
* @throws MalformedURLException if no valid jar file URL could be extracted
* @since 4.1.8
* @see #extractJarFileURL(URL)
*/
public static URL extractArchiveURL(URL jarUrl) throws MalformedURLException {
String urlFile = jarUrl.getFile();
int endIndex = urlFile.indexOf(WAR_URL_SEPARATOR);
if (endIndex != -1) {
// Tomcat's "war:file:...mywar.war*/WEB-INF/lib/myjar.jar!/myentry.txt"
String warFile = urlFile.substring(0, endIndex);
if (URL_PROTOCOL_WAR.equals(jarUrl.getProtocol())) {
return toURL(warFile);
}
int startIndex = warFile.indexOf(WAR_URL_PREFIX);
if (startIndex != -1) {
return toURL(warFile.substring(startIndex + WAR_URL_PREFIX.length()));
}
}
// Regular "jar:file:...myjar.jar!/myentry.txt"
return extractJarFileURL(jarUrl);
}
/**
* Create a URI instance for the given URL,
* replacing spaces with "%20" URI encoding first.
* @param url the URL to convert into a URI instance
* @return the URI instance
* @throws URISyntaxException if the URL wasn't a valid URI
* @see java.net.URL#toURI()
*/
public static URI toURI(URL url) throws URISyntaxException {
return toURI(url.toString());
}
/**
* Create a URI instance for the given location String,
* replacing spaces with "%20" URI encoding first.
* @param location the location String to convert into a URI instance
* @return the URI instance
* @throws URISyntaxException if the location wasn't a valid URI
*/
public static URI toURI(String location) throws URISyntaxException {
return new URI(StringUtils.replace(location, " ", "%20"));
}
/**
* Create a URL instance for the given location String,
* going through URI construction and then URL conversion.
* @param location the location String to convert into a URL instance
* @return the URL instance
* @throws MalformedURLException if the location wasn't a valid URL
* @since 6.0
*/
public static URL toURL(String location) throws MalformedURLException {
// Equivalent without java.net.URL constructor - for building on JDK 20+
/*
try {
return toURI(StringUtils.cleanPath(location)).toURL();
}
catch (URISyntaxException | IllegalArgumentException ex) {
MalformedURLException exToThrow = new MalformedURLException(ex.getMessage());
exToThrow.initCause(ex);
throw exToThrow;
}
*/
return new URL(location);
}
/**
* Create a URL instance for the given root URL and relative path,
* going through URI construction and then URL conversion.
* @param root the root URL to start from
* @param relativePath the relative path to apply
* @return the relative URL instance
* @throws MalformedURLException if the end result is not a valid URL
* @since 6.0
*/
public static URL toRelativeURL(URL root, String relativePath) throws MalformedURLException {
// # can appear in filenames, java.net.URL should not treat it as a fragment
relativePath = StringUtils.replace(relativePath, "#", "%23");
// Equivalent without java.net.URL constructor - for building on JDK 20+
/*
return toURL(StringUtils.applyRelativePath(root.toString(), relativePath));
*/
return new URL(root, relativePath);
}
/**
* Set the {@link URLConnection#setUseCaches "useCaches"} flag on the
* given connection, preferring {@code false} but leaving the
* flag at {@code true} for JNLP based resources.
* @param con the URLConnection to set the flag on
*/
public static void useCachesIfNecessary(URLConnection con) {
con.setUseCaches(con.getClass().getSimpleName().startsWith("JNLP"));
}
}