Package 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 an Resource object, which in turn allows one to obtain a java.io.File in the file system through its getFile() method.

Since:
1.1.5
Author:
Juergen Hoeller
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    CLASSPATH_URL_PREFIX
    Pseudo URL prefix for loading from the class path: "classpath:".
    static final String
    FILE_URL_PREFIX
    URL prefix for loading from the file system: "file:".
    static final String
    JAR_FILE_EXTENSION
    File extension for a regular jar file: ".jar".
    static final String
    JAR_URL_PREFIX
    URL prefix for loading from a jar file: "jar:".
    static final String
    JAR_URL_SEPARATOR
    Separator between JAR URL and file path within the JAR: "!/".
    static final String
    URL_PROTOCOL_FILE
    URL protocol for a file in the file system: "file".
    static final String
    URL_PROTOCOL_JAR
    URL protocol for an entry from a jar file: "jar".
    static final String
    URL_PROTOCOL_VFS
    URL protocol for a general JBoss VFS resource: "vfs".
    static final String
    URL_PROTOCOL_VFSFILE
    URL protocol for a JBoss file system resource: "vfsfile".
    static final String
    URL_PROTOCOL_VFSZIP
    URL protocol for an entry from a JBoss jar file: "vfszip".
    static final String
    URL_PROTOCOL_WAR
    URL protocol for an entry from a war file: "war".
    static final String
    URL_PROTOCOL_WSJAR
    URL protocol for an entry from a WebSphere jar file: "wsjar".
    static final String
    URL_PROTOCOL_ZIP
    URL protocol for an entry from a zip file: "zip".
    static final String
    WAR_URL_PREFIX
    URL prefix for loading from a war file on Tomcat: "war:".
    static final String
    WAR_URL_SEPARATOR
    Special separator between WAR URL and jar part on Tomcat.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ResourceUtils()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static URL
    extractArchiveURL(URL 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).
    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, i.e.
    static boolean
    isJarFileURL(URL url)
    Determine whether the given URL points to a jar file itself, that is, has protocol "file" and ends with the ".jar" extension.
    static boolean
    isJarURL(URL url)
    Determine whether the given URL points to a resource in a jar file — for example, whether the URL has protocol "jar", "war, "zip", "vfszip", or "wsjar".
    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 URL
    toRelativeURL(URL root, String relativePath)
    Create a URL instance for the given root URL and relative path, going through URI construction and then URL conversion.
    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 URL
    toURL(String location)
    Create a URL instance for the given location String, going through URI construction and then URL conversion.
    static void
    useCachesIfNecessary(URLConnection con)
    Set the "useCaches" flag on the given connection, preferring false but leaving the flag at its JVM default value for jar resources (typically true).

    Methods inherited from class java.lang.Object

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

  • Field Details

    • CLASSPATH_URL_PREFIX

      public static final String CLASSPATH_URL_PREFIX
      Pseudo URL prefix for loading from the class path: "classpath:".
      See Also:

    • FILE_URL_PREFIX

      public static final String FILE_URL_PREFIX
      URL prefix for loading from the file system: "file:".
      See Also:

    • JAR_URL_PREFIX

      public static final String JAR_URL_PREFIX
      URL prefix for loading from a jar file: "jar:".
      See Also:

    • WAR_URL_PREFIX

      public static final String WAR_URL_PREFIX
      URL prefix for loading from a war file on Tomcat: "war:".
      See Also:

    • URL_PROTOCOL_FILE

      public static final String URL_PROTOCOL_FILE
      URL protocol for a file in the file system: "file".
      See Also:

    • URL_PROTOCOL_JAR

      public static final String URL_PROTOCOL_JAR
      URL protocol for an entry from a jar file: "jar".
      See Also:

    • URL_PROTOCOL_WAR

      public static final String URL_PROTOCOL_WAR
      URL protocol for an entry from a war file: "war".
      See Also:

    • URL_PROTOCOL_ZIP

      public static final String URL_PROTOCOL_ZIP
      URL protocol for an entry from a zip file: "zip".
      See Also:

    • URL_PROTOCOL_WSJAR

      public static final String URL_PROTOCOL_WSJAR
      URL protocol for an entry from a WebSphere jar file: "wsjar".
      See Also:

    • URL_PROTOCOL_VFSZIP

      public static final String URL_PROTOCOL_VFSZIP
      URL protocol for an entry from a JBoss jar file: "vfszip".
      See Also:

    • URL_PROTOCOL_VFSFILE

      public static final String URL_PROTOCOL_VFSFILE
      URL protocol for a JBoss file system resource: "vfsfile".
      See Also:

    • URL_PROTOCOL_VFS

      public static final String URL_PROTOCOL_VFS
      URL protocol for a general JBoss VFS resource: "vfs".
      See Also:

    • JAR_FILE_EXTENSION

      public static final String JAR_FILE_EXTENSION
      File extension for a regular jar file: ".jar".
      See Also:

    • JAR_URL_SEPARATOR

      public static final String JAR_URL_SEPARATOR
      Separator between JAR URL and file path within the JAR: "!/".
      See Also:

    • WAR_URL_SEPARATOR

      public static final String WAR_URL_SEPARATOR
      Special separator between WAR URL and jar part on Tomcat.
      See Also:

  • Constructor Details

    • ResourceUtils

      public ResourceUtils()

  • Method Details

    • isUrl

      public static boolean isUrl(@Nullable 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:

    • 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
      Since:
      2.5

    • 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
      Since:
      2.5

    • isFileURL

      public static boolean isFileURL(URL url)
      Determine whether the given URL points to a resource in the file system, i.e. 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 — for example, whether the URL has protocol "jar", "war, "zip", "vfszip", or "wsjar".
      Parameters:
      url - the URL to check
      Returns:
      whether the URL has been identified as a JAR URL

    • isJarFileURL

      public static boolean isJarFileURL(URL url)
      Determine whether the given URL points to a jar file itself, that is, has protocol "file" and ends with the ".jar" extension.
      Parameters:
      url - the URL to check
      Returns:
      whether the URL has been identified as a JAR file URL
      Since:
      4.1

    • 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

    • extractArchiveURL

      public static URL extractArchiveURL(URL jarUrl) throws MalformedURLException
      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.

      Parameters:
      jarUrl - the original URL
      Returns:
      the URL for the actual jar file
      Throws:
      MalformedURLException - if no valid jar file URL could be extracted
      Since:
      4.1.8
      See Also:

    • toURI

      public static URI toURI(URL url) throws URISyntaxException
      Create a URI instance for the given URL, replacing spaces with "%20" URI encoding first.
      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:

    • 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

    • toURL

      public static URL toURL(String location) throws MalformedURLException
      Create a URL instance for the given location String, going through URI construction and then URL conversion.
      Parameters:
      location - the location String to convert into a URL instance
      Returns:
      the URL instance
      Throws:
      MalformedURLException - if the location wasn't a valid URL
      Since:
      6.0

    • toRelativeURL

      public static URL toRelativeURL(URL root, String relativePath) throws MalformedURLException
      Create a URL instance for the given root URL and relative path, going through URI construction and then URL conversion.
      Parameters:
      root - the root URL to start from
      relativePath - the relative path to apply
      Returns:
      the relative URL instance
      Throws:
      MalformedURLException - if the end result is not a valid URL
      Since:
      6.0

    • useCachesIfNecessary

      public static void useCachesIfNecessary(URLConnection con)
      Set the "useCaches" flag on the given connection, preferring false but leaving the flag at its JVM default value for jar resources (typically true).
      Parameters:
      con - the URLConnection to set the flag on