Class DiskFileItem

  • All Implemented Interfaces:
    FileItem<DiskFileItem>, FileItemHeadersProvider<DiskFileItem>

    public final class DiskFileItem
    extends Object
    implements FileItem<DiskFileItem>
    The default implementation of the FileItem interface.

    After retrieving an instance of this class from a DiskFileItemFactory instance (see org.apache.commons.fileupload2.core.servlet.ServletFileUpload #parseRequest(javax.servlet.http.HttpServletRequest)), you may either request all contents of file at once using get() or request an InputStream with getInputStream() and process the file without attempting to load it into memory, which may come handy with large files.

    Temporary files, which are created for file items, should be deleted later on. The best way to do this is using a FileCleaningTracker, which you can set on the DiskFileItemFactory. However, if you do use such a tracker, then you must consider the following: Temporary files are automatically deleted as soon as they are no longer needed. (More precisely, when the corresponding instance of File is garbage collected.) This is done by the so-called reaper thread, which is started and stopped automatically by the FileCleaningTracker when there are files to be tracked. It might make sense to terminate that thread, for example, if your web application ends. See the section on "Resource cleanup" in the users guide of Commons FileUpload.

    • Field Detail

      • DEFAULT_CHARSET

        public static final Charset DEFAULT_CHARSET
        Default content charset to be used when no explicit charset parameter is provided by the sender. Media subtypes of the "text" type are defined to have a default charset value of "ISO-8859-1" when received via HTTP.
    • Method Detail

      • checkFileName

        public static String checkFileName​(String fileName)
        Tests if the file name is valid. For example, if it contains a NUL characters, it's invalid. If the file name is valid, it will be returned without any modifications. Otherwise, throw an InvalidPathException.
        Parameters:
        fileName - The file name to check
        Returns:
        Unmodified file name, if valid.
        Throws:
        InvalidPathException - The file name is invalid.
      • delete

        public DiskFileItem delete()
                            throws IOException
        Deletes the underlying storage for a file item, including deleting any associated temporary disk file. This method can be used to ensure that this is done at an earlier time, thus preserving system resources.
        Specified by:
        delete in interface FileItem<DiskFileItem>
        Returns:
        this
        Throws:
        IOException - if an error occurs.
      • get

        public byte[] get()
                   throws UncheckedIOException
        Gets the contents of the file as an array of bytes. If the contents of the file were not yet cached in memory, they will be loaded from the disk storage and cached.
        Specified by:
        get in interface FileItem<DiskFileItem>
        Returns:
        The contents of the file as an array of bytes or null if the data cannot be read.
        Throws:
        UncheckedIOException - if an I/O error occurs.
        OutOfMemoryError - See Files.readAllBytes(Path): If an array of the required size cannot be allocated, for example the file is larger that 2GB
      • getCharset

        public Charset getCharset()
        Gets the content charset passed by the agent or null if not defined.
        Returns:
        The content charset passed by the agent or null if not defined.
      • getCharsetDefault

        public Charset getCharsetDefault()
        Gets the default charset for use when no explicit charset parameter is provided by the sender.
        Returns:
        the default charset
      • getPath

        public Path getPath()
        Gets the Path for the FileItem's data's temporary location on the disk. Note that for FileItems that have their data stored in memory, this method will return null. When handling large files, you can use Files.move(Path,Path,CopyOption...) to move the file to new location without copying the data, if the source and destination locations reside within the same logical volume.
        Returns:
        The data file, or null if the data is stored in memory.
      • getString

        public String getString()
        Gets the contents of the file as a String, using the default character encoding. This method uses get() to retrieve the contents of the file.

        TODO Consider making this method throw UnsupportedEncodingException.

        Specified by:
        getString in interface FileItem<DiskFileItem>
        Returns:
        The contents of the file, as a string.
      • getString

        public String getString​(Charset charset)
                         throws IOException
        Gets the contents of the file as a String, using the specified encoding. This method uses get() to retrieve the contents of the file.
        Specified by:
        getString in interface FileItem<DiskFileItem>
        Parameters:
        charset - The charset to use.
        Returns:
        The contents of the file, as a string.
        Throws:
        IOException - if an I/O error occurs
      • getTempFile

        protected Path getTempFile()
        Creates and returns a File representing a uniquely named temporary file in the configured repository path. The lifetime of the file is tied to the lifetime of the FileItem instance; the file will be deleted when the instance is garbage collected.

        Note: Subclasses that override this method must ensure that they return the same File each time.

        Returns:
        The File to be used for temporary storage.
      • isFormField

        public boolean isFormField()
        Tests whether or not a FileItem instance represents a simple form field.
        Specified by:
        isFormField in interface FileItem<DiskFileItem>
        Returns:
        true if the instance represents a simple form field; false if it represents an uploaded file.
        See Also:
        setFormField(boolean)
      • isInMemory

        public boolean isInMemory()
        Provides a hint as to whether or not the file contents will be read from memory.
        Specified by:
        isInMemory in interface FileItem<DiskFileItem>
        Returns:
        true if the file contents will be read from memory; false otherwise.
      • setCharsetDefault

        public DiskFileItem setCharsetDefault​(Charset charset)
        Sets the default charset for use when no explicit charset parameter is provided by the sender.
        Parameters:
        charset - the default charset
        Returns:
        this
      • setFormField

        public DiskFileItem setFormField​(boolean state)
        Specifies whether or not a FileItem instance represents a simple form field.
        Specified by:
        setFormField in interface FileItem<DiskFileItem>
        Parameters:
        state - true if the instance represents a simple form field; false if it represents an uploaded file.
        Returns:
        this
        See Also:
        isFormField()
      • toString

        public String toString()
        Returns a string representation of this object.
        Overrides:
        toString in class Object
        Returns:
        a string representation of this object.
      • write

        public DiskFileItem write​(Path file)
                           throws IOException
        Writes an uploaded item to disk.

        The client code is not concerned with whether or not the item is stored in memory, or on disk in a temporary location. They just want to write the uploaded item to a file.

        This implementation first attempts to rename the uploaded item to the specified destination file, if the item was originally written to disk. Otherwise, the data will be copied to the specified file.

        This method is only guaranteed to work once, the first time it is invoked for a particular item. This is because, in the event that the method renames a temporary file, that file will no longer be available to copy or rename again at a later time.

        Specified by:
        write in interface FileItem<DiskFileItem>
        Parameters:
        file - The File into which the uploaded item should be stored.
        Returns:
        this
        Throws:
        IOException - if an error occurs.