org.springframework.util
Class ResourceUtils

java.lang.Object
  org.springframework.util.ResourceUtils

public abstract class ResourceUtils
extends Object

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. ResourceLoader's getResource method can resolve any location to a Resource object, which in turn allows to obtain a java.io.File in the file system through its getFile() method.

The main reason for these utility methods for resource location handling is to support Log4jConfigurer, which must be able to resolve resource locations before the logging system has been initialized. Spring' Resource abstraction in the core package, on the other hand, already expects the logging system to be available.

Since:

1.1.5

Author:

Juergen Hoeller

See Also:

Resource, ClassPathResource, FileSystemResource, UrlResource, ResourceLoader

Field Summary

static String	CLASSPATH_URL_PREFIX Pseudo URL prefix for loading from the class path: "classpath:"
static String	FILE_URL_PREFIX URL prefix for loading from the file system: "file:"
static String	JAR_URL_SEPARATOR Separator between JAR URL and file path within the JAR
static String	URL_PROTOCOL_CODE_SOURCE URL protocol for an entry from an OC4J jar file: "code-source"
static String	URL_PROTOCOL_FILE URL protocol for a file in the file system: "file"
static String	URL_PROTOCOL_JAR URL protocol for an entry from a jar file: "jar"
static String	URL_PROTOCOL_VFS URL protocol for a JBoss VFS resource: "vfs"
static String	URL_PROTOCOL_VFSZIP URL protocol for an entry from a JBoss jar file: "vfszip"
static String	URL_PROTOCOL_WSJAR URL protocol for an entry from a WebSphere jar file: "wsjar"
static String	URL_PROTOCOL_ZIP URL protocol for an entry from a zip file: "zip"

Constructor Summary

ResourceUtils()

Method Summary

static URL	extractJarFileURL(URL jarUrl) 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).
static File	getFile(String resourceLocation) Resolve the given resource location to a java.io.File, i.e.
static File	getFile(URI resourceUri) Resolve the given resource URI to a java.io.File, i.e.
static File	getFile(URI resourceUri, String description) Resolve the given resource URI to a java.io.File, i.e.
static File	getFile(URL resourceUrl) Resolve the given resource URL to a java.io.File, i.e.
static File	getFile(URL resourceUrl, String description) Resolve the given resource URL to a java.io.File, i.e.
static URL	getURL(String resourceLocation) Resolve the given resource location to a java.net.URL.
static boolean	isFileURL(URL url) Determine whether the given URL points to a resource in the file system, that is, has protocol "file" or "vfs".
static boolean	isJarURL(URL url) Determine whether the given URL points to a resource in a jar file, that is, has protocol "jar", "zip", "wsjar" or "code-source".
static boolean	isUrl(String resourceLocation) Return whether the given resource location is a URL: either a special "classpath" pseudo URL or a standard URL.
static URI	toURI(String location) Create a URI instance for the given location String, replacing spaces with "%20" quotes first.
static URI	toURI(URL url) Create a URI instance for the given URL, replacing spaces with "%20" quotes first.
static void	useCachesIfNecessary(URLConnection con) Set the "useCaches" flag on the given connection, preferring false but leaving the flag at true for JNLP based resources.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CLASSPATH_URL_PREFIX

public static final String CLASSPATH_URL_PREFIX

Pseudo URL prefix for loading from the class path: "classpath:"

See Also:

Constant Field Values

FILE_URL_PREFIX

public static final String FILE_URL_PREFIX

URL prefix for loading from the file system: "file:"

See Also:

Constant Field Values

URL_PROTOCOL_FILE

public static final String URL_PROTOCOL_FILE

URL protocol for a file in the file system: "file"

See Also:

Constant Field Values

URL_PROTOCOL_JAR

public static final String URL_PROTOCOL_JAR

URL protocol for an entry from a jar file: "jar"

See Also:

Constant Field Values

URL_PROTOCOL_ZIP

public static final String URL_PROTOCOL_ZIP

URL protocol for an entry from a zip file: "zip"

See Also:

Constant Field Values

URL_PROTOCOL_VFSZIP

public static final String URL_PROTOCOL_VFSZIP

URL protocol for an entry from a JBoss jar file: "vfszip"

See Also:

Constant Field Values

URL_PROTOCOL_VFS

public static final String URL_PROTOCOL_VFS

URL protocol for a JBoss VFS resource: "vfs"

See Also:

Constant Field Values

URL_PROTOCOL_WSJAR

public static final String URL_PROTOCOL_WSJAR

URL protocol for an entry from a WebSphere jar file: "wsjar"

See Also:

Constant Field Values

URL_PROTOCOL_CODE_SOURCE

public static final String URL_PROTOCOL_CODE_SOURCE

URL protocol for an entry from an OC4J jar file: "code-source"

See Also:

Constant Field Values

JAR_URL_SEPARATOR

public static final String JAR_URL_SEPARATOR

Separator between JAR URL and file path within the JAR

See Also:

Constant Field Values

Constructor Detail

ResourceUtils

public ResourceUtils()

Method Detail

isUrl

public static boolean isUrl(String resourceLocation)

Return whether the given resource location is a URL: either a special "classpath" pseudo URL or a standard URL.

Parameters:

resourceLocation - the location String to check

Returns:

whether the location qualifies as a URL

See Also:

CLASSPATH_URL_PREFIX, URL

getURL

public static URL getURL(String resourceLocation)
                  throws FileNotFoundException

Resolve the given resource location to a java.net.URL.

Does not check whether the URL actually exists; simply returns the URL that the given location would correspond to.

Parameters:

resourceLocation - the resource location to resolve: either a "classpath:" pseudo URL, a "file:" URL, or a plain file path

Returns:

a corresponding URL object

Throws:

FileNotFoundException - if the resource cannot be resolved to a URL

getFile

public static File getFile(String resourceLocation)
                    throws FileNotFoundException

Resolve the given resource location to a java.io.File, i.e. to a file in the file system.

Does not check whether the fil actually exists; simply returns the File that the given location would correspond to.

Parameters:

resourceLocation - the resource location to resolve: either a "classpath:" pseudo URL, a "file:" URL, or a plain file path

Returns:

a corresponding File object

Throws:

FileNotFoundException - if the resource cannot be resolved to a file in the file system

getFile

public static File getFile(URL resourceUrl)
                    throws FileNotFoundException

Resolve the given resource URL to a java.io.File, i.e. to a file in the file system.

Parameters:

resourceUrl - the resource URL to resolve

Returns:

a corresponding File object

Throws:

FileNotFoundException - if the URL cannot be resolved to a file in the file system

getFile

public static File getFile(URL resourceUrl,
                           String description)
                    throws FileNotFoundException

Resolve the given resource URL to a java.io.File, i.e. to a file in the file system.

Parameters:

resourceUrl - the resource URL to resolve

description - a description of the original resource that the URL was created for (for example, a class path location)

Returns:

a corresponding File object

Throws:

FileNotFoundException - if the URL cannot be resolved to a file in the file system

getFile

public static File getFile(URI resourceUri)
                    throws FileNotFoundException

Resolve the given resource URI to a java.io.File, i.e. to a file in the file system.

Parameters:

resourceUri - the resource URI to resolve

Returns:

a corresponding File object

Throws:

FileNotFoundException - if the URL cannot be resolved to a file in the file system

getFile

public static File getFile(URI resourceUri,
                           String description)
                    throws FileNotFoundException

Resolve the given resource URI to a java.io.File, i.e. to a file in the file system.

Parameters:

resourceUri - the resource URI to resolve

description - a description of the original resource that the URI was created for (for example, a class path location)

Returns:

a corresponding File object

Throws:

FileNotFoundException - if the URL cannot be resolved to a file in the file system

isFileURL

public static boolean isFileURL(URL url)

Determine whether the given URL points to a resource in the file system, that is, has protocol "file" or "vfs".

Parameters:

url - the URL to check

Returns:

whether the URL has been identified as a file system URL

isJarURL

public static boolean isJarURL(URL url)

Determine whether the given URL points to a resource in a jar file, that is, has protocol "jar", "zip", "wsjar" or "code-source".

"zip" and "wsjar" are used by BEA WebLogic Server and IBM WebSphere, respectively, but can be treated like jar files. The same applies to "code-source" URLs on Oracle OC4J, provided that the path contains a jar separator.

Parameters:

url - the URL to check

Returns:

whether the URL has been identified as a JAR URL

extractJarFileURL

public static URL extractJarFileURL(URL jarUrl)
                             throws MalformedURLException

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).

Parameters:

jarUrl - the original URL

Returns:

the URL for the actual jar file

Throws:

MalformedURLException - if no valid jar file URL could be extracted

toURI

public static URI toURI(URL url)
                 throws URISyntaxException

Create a URI instance for the given URL, replacing spaces with "%20" quotes first.

Furthermore, this method works on JDK 1.4 as well, in contrast to the URL.toURI() method.

Parameters:

url - the URL to convert into a URI instance

Returns:

the URI instance

Throws:

URISyntaxException - if the URL wasn't a valid URI

See Also:

URL.toURI()

toURI

public static URI toURI(String location)
                 throws URISyntaxException

Create a URI instance for the given location String, replacing spaces with "%20" quotes first.

Parameters:

location - the location String to convert into a URI instance

Returns:

the URI instance

Throws:

URISyntaxException - if the location wasn't a valid URI

useCachesIfNecessary

public static void useCachesIfNecessary(URLConnection con)

Set the "useCaches" flag on the given connection, preferring false but leaving the flag at true for JNLP based resources.

Parameters:

con - the URLConnection to set the flag on