Package org.springframework.core.io

Interface Resource

All Superinterfaces:
InputStreamSource
All Known Subinterfaces:
ContextResource, HttpResource, HttpResource, WritableResource
All Known Implementing Classes:
AbstractFileResolvingResource, AbstractResource, ByteArrayResource, ClassPathResource, DefaultResourceLoader.ClassPathContextResource, DescriptiveResource, FileSystemResource, FileUrlResource, InputStreamResource, PathResource, ServletContextResource, TransformedResource, TransformedResource, UrlResource, VfsResource
public interface Resource extends InputStreamSource
Interface for a resource descriptor that abstracts from the actual type of underlying resource, such as a file or class path resource.

An InputStream can be opened for every resource if it exists in physical form, but a URL or File handle can just be returned for certain resources. The actual behavior is implementation-specific.

Since:
28.12.2003
Author:
Juergen Hoeller, Arjen Poutsma
See Also:

  • Method Details

    • exists

      boolean exists()
      Determine whether this resource actually exists in physical form.

      This method performs a definitive existence check, whereas the existence of a Resource handle only guarantees a valid descriptor handle.

    • isReadable

      default boolean isReadable()
      Indicate whether non-empty contents of this resource can be read via InputStreamSource.getInputStream().

      Will be true for typical resource descriptors that exist since it strictly implies exists() semantics as of 5.1. Note that actual content reading may still fail when attempted. However, a value of false is a definitive indication that the resource content cannot be read.

      See Also:

    • isOpen

      default boolean isOpen()
      Indicate whether this resource represents a handle with an open stream. If true, the InputStream cannot be read multiple times, and must be read and closed to avoid resource leaks.

      Will be false for typical resource descriptors.

    • isFile

      default boolean isFile()
      Determine whether this resource represents a file in a file system.

      A value of true strongly suggests (but does not guarantee) that a getFile() call will succeed.

      This is conservatively false by default.

      Since:
      5.0
      See Also:

    • getURL

      URL getURL() throws IOException
      Return a URL handle for this resource.
      Throws:
      IOException - if the resource cannot be resolved as URL, i.e. if the resource is not available as a descriptor

    • getURI

      URI getURI() throws IOException
      Return a URI handle for this resource.
      Throws:
      IOException - if the resource cannot be resolved as URI, i.e. if the resource is not available as a descriptor
      Since:
      2.5

    • getFile

      File getFile() throws IOException
      Return a File handle for this resource.
      Throws:
      FileNotFoundException - if the resource cannot be resolved as absolute file path, i.e. if the resource is not available in a file system
      IOException - in case of general resolution/reading failures
      See Also:

    • readableChannel

      default ReadableByteChannel readableChannel() throws IOException
      Return a ReadableByteChannel.

      It is expected that each call creates a fresh channel.

      The default implementation returns Channels.newChannel(InputStream) with the result of InputStreamSource.getInputStream().

      Returns:
      the byte channel for the underlying resource (must not be null)
      Throws:
      FileNotFoundException - if the underlying resource doesn't exist
      IOException - if the content channel could not be opened
      Since:
      5.0
      See Also:

    • getContentAsByteArray

      default byte[] getContentAsByteArray() throws IOException
      Return the contents of this resource as a byte array.
      Returns:
      the contents of this resource as byte array
      Throws:
      FileNotFoundException - if the resource cannot be resolved as absolute file path, i.e. if the resource is not available in a file system
      IOException - in case of general resolution/reading failures
      Since:
      6.0.5

    • getContentAsString

      default String getContentAsString(Charset charset) throws IOException
      Returns the contents of this resource as a string, using the specified charset.
      Parameters:
      charset - the charset to use for decoding
      Returns:
      the contents of this resource as a String
      Throws:
      FileNotFoundException - if the resource cannot be resolved as absolute file path, i.e. if the resource is not available in a file system
      IOException - in case of general resolution/reading failures
      Since:
      6.0.5

    • contentLength

      long contentLength() throws IOException
      Determine the content length for this resource.
      Throws:
      IOException - if the resource cannot be resolved (in the file system or as some other known physical resource type)

    • lastModified

      long lastModified() throws IOException
      Determine the last-modified timestamp for this resource.
      Throws:
      IOException - if the resource cannot be resolved (in the file system or as some other known physical resource type)

    • createRelative

      Resource createRelative(String relativePath) throws IOException
      Create a resource relative to this resource.
      Parameters:
      relativePath - the relative path (relative to this resource)
      Returns:
      the resource handle for the relative resource
      Throws:
      IOException - if the relative resource cannot be determined

    • getFilename

      @Nullable String getFilename()
      Determine the filename for this resource — typically the last part of the path — for example, "myfile.txt".

      Returns null if this type of resource does not have a filename.

      Implementations are encouraged to return the filename unencoded.

    • getDescription

      String getDescription()
      Return a description for this resource, to be used for error output when working with the resource.

      Implementations are also encouraged to return this value from their toString method.

      See Also: