org.springframework.util

Class 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 one 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's 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
    • Constructor Summary

      Constructors  
      Constructor and Description
      ResourceUtils() 
    • Method Summary

      Methods  
      Modifier and Type Method and Description
      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", "vfsfile" 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", "vfszip", "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" URI encoding first.
      static URI toURI(URL url)
      Create a URI instance for the given URL, replacing spaces with "%20" URI encoding 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.
    • 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_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_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_VFSFILE

        public static final String URL_PROTOCOL_VFSFILE
        URL protocol for a JBoss file system resource: "vfsfile"
        See Also:
        Constant Field Values
      • URL_PROTOCOL_VFS

        public static final String URL_PROTOCOL_VFS
        URL protocol for a general JBoss VFS resource: "vfs"
        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 file 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", "vfsfile" 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", "vfszip", "wsjar" or "code-source".

        "zip" and "wsjar" are used by WebLogic Server and WebSphere, respectively, but can be treated like jar files. The same applies to "code-source" URLs on 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" URI encoding 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" URI encoding 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