Package org.apache.commons.fileupload.disk

Class DiskFileItem

java.lang.Object
org.apache.commons.fileupload.disk.DiskFileItem
All Implemented Interfaces:
FileItem, FileItemHeadersSupport
Direct Known Subclasses:
DefaultFileItem
public class DiskFileItem extends Object implements FileItem
The default implementation of the FileItem interface.

After retrieving an instance of this class from a DiskFileItemFactory instance (see #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.

Since:
FileUpload 1.1

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private byte[]
    cachedContent
    Cached contents of the file.
    private final String
    contentType
    The content type passed by the browser, or null if not defined.
    private static final AtomicInteger
    COUNTER
    Counter used in unique identifier generation.
    static final String
    DEFAULT_CHARSET
    Default content charset to be used when no explicit charset parameter is provided by the sender.
    private String
    defaultCharset
    Default content charset to be used when no explicit charset parameter is provided by the sender.
    private org.apache.commons.io.output.DeferredFileOutputStream
    dfos
    Output stream for this item.
    private String
    fieldName
    The name of the form field as provided by the browser.
    private final String
    fileName
    The original file name in the user's file system.
    private boolean
    formField
    Whether or not this item is a simple form field.
    private FileItemHeaders
    headers
    The file items headers.
    private final File
    repository
    The directory in which uploaded files will be stored, if stored on disk.
    private long
    size
    The size of the item, in bytes.
    private final int
    sizeThreshold
    The threshold above which uploads will be stored on disk.
    private File
    tempFile
    The temporary file to use.
    private static final String
    UID
    UID used in unique file name generation.

  • Constructor Summary

    Constructors
    Constructor
    Description
    DiskFileItem(String fieldName, String contentType, boolean isFormField, String fileName, int sizeThreshold, File repository)
    Constructs a new DiskFileItem instance.

  • Method Summary

    Modifier and Type
    Method
    Description
    private void
    clear()
    Clears the cache.
    void
    delete()
    Deletes the underlying storage for a file item, including deleting any associated temporary disk file.
    protected void
    finalize()
    Removes the file contents from the temporary storage.
    byte[]
    get()
    Gets the contents of the file as an array of bytes.
    String
    getCharSet()
    Gets the content charset passed by the agent or null if not defined.
    String
    getContentType()
    Gets the content type passed by the agent or null if not defined.
    String
    getDefaultCharset()
    Gets the default charset for use when no explicit charset parameter is provided by the sender.
    String
    getFieldName()
    Gets the name of the field in the multipart form corresponding to this file item.
    FileItemHeaders
    getHeaders()
    Gets the file item headers.
    InputStream
    getInputStream()
    Gets an InputStream that can be used to retrieve the contents of the file.
    String
    getName()
    Gets the original file name in the client's file system.
    OutputStream
    getOutputStream()
    Gets an OutputStream that can be used for storing the contents of the file.
    long
    getSize()
    Gets the size of the file.
    File
    getStoreLocation()
    Gets the File object for the FileItem's data's temporary location on the disk.
    String
    getString()
    Gets the contents of the file as a String, using the default character encoding.
    String
    getString(String charset)
    Gets the contents of the file as a String, using the specified encoding.
    protected File
    getTempFile()
    Creates and returns a File representing a uniquely named temporary file in the configured repository path.
    private static String
    getUniqueId()
    Returns an identifier that is unique within the class loader used to load this class, but does not have random-like appearance.
    boolean
    isFormField()
    Tests whether or not a FileItem instance represents a simple form field.
    boolean
    isInMemory()
    Provides a hint as to whether or not the file contents will be read from memory.
    void
    setDefaultCharset(String charset)
    Sets the default charset for use when no explicit charset parameter is provided by the sender.
    void
    setFieldName(String fieldName)
    Sets the field name used to reference this file item.
    void
    setFormField(boolean formField)
    Sets whether or not a FileItem instance represents a simple form field.
    void
    setHeaders(FileItemHeaders headers)
    Sets the file item headers.
    String
    toString()
    Returns a string representation of this object.
    void
    write(File file)
    A convenience method to write an uploaded item to disk.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • COUNTER

      private static final AtomicInteger COUNTER
      Counter used in unique identifier generation.

    • DEFAULT_CHARSET

      public static final String 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.
      See Also:

    • UID

      private static final String UID
      UID used in unique file name generation.

    • cachedContent

      private byte[] cachedContent
      Cached contents of the file.

    • contentType

      private final String contentType
      The content type passed by the browser, or null if not defined.

    • defaultCharset

      private String defaultCharset
      Default content charset to be used when no explicit charset parameter is provided by the sender.

    • dfos

      private transient org.apache.commons.io.output.DeferredFileOutputStream dfos
      Output stream for this item.

    • fieldName

      private String fieldName
      The name of the form field as provided by the browser.

    • fileName

      private final String fileName
      The original file name in the user's file system.

    • headers

      private FileItemHeaders headers
      The file items headers.

    • formField

      private boolean formField
      Whether or not this item is a simple form field.

    • repository

      private final File repository
      The directory in which uploaded files will be stored, if stored on disk.

    • size

      private long size
      The size of the item, in bytes. This is used to cache the size when a file item is moved from its original location.

    • sizeThreshold

      private final int sizeThreshold
      The threshold above which uploads will be stored on disk.

    • tempFile

      private transient File tempFile
      The temporary file to use.

  • Constructor Details

    • DiskFileItem

      public DiskFileItem(String fieldName, String contentType, boolean isFormField, String fileName, int sizeThreshold, File repository)
      Constructs a new DiskFileItem instance.
      Parameters:
      fieldName - The name of the form field.
      contentType - The content type passed by the browser or null if not specified.
      isFormField - Whether or not this item is a plain form field, as opposed to a file upload.
      fileName - The original file name in the user's file system, or null if not specified.
      sizeThreshold - The threshold, in bytes, below which items will be retained in memory and above which they will be stored as a file.
      repository - The data repository, which is the directory in which files will be created, should the item size exceed the threshold.

  • Method Details

    • getUniqueId

      private static String getUniqueId()
      Returns an identifier that is unique within the class loader used to load this class, but does not have random-like appearance.
      Returns:
      A String with the non-random looking instance identifier.

    • clear

      private void clear()
      Clears the cache.

    • delete

      public void delete()
      Deletes the underlying storage for a file item, including deleting any associated temporary disk file. Although this storage will be deleted automatically when the FileItem instance is garbage collected, 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

    • finalize

      protected void finalize() throws Throwable
      Removes the file contents from the temporary storage.
      Overrides:
      finalize in class Object
      Throws:
      Throwable - Thrown by Object.finalize().

    • get

      public byte[] get()
      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
      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 - if an array of the required size cannot be allocated, for example the file is larger that 2GB.

    • getCharSet

      public String 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.

    • getContentType

      public String getContentType()
      Gets the content type passed by the agent or null if not defined.
      Specified by:
      getContentType in interface FileItem
      Returns:
      The content type passed by the agent or null if not defined.

    • getDefaultCharset

      public String getDefaultCharset()
      Gets the default charset for use when no explicit charset parameter is provided by the sender.
      Returns:
      the default charset

    • getFieldName

      public String getFieldName()
      Gets the name of the field in the multipart form corresponding to this file item.
      Specified by:
      getFieldName in interface FileItem
      Returns:
      The name of the form field.
      See Also:

    • getHeaders

      public FileItemHeaders getHeaders()
      Gets the file item headers.
      Specified by:
      getHeaders in interface FileItemHeadersSupport
      Returns:
      The file items headers.

    • getInputStream

      public InputStream getInputStream() throws IOException
      Gets an InputStream that can be used to retrieve the contents of the file.
      Specified by:
      getInputStream in interface FileItem
      Returns:
      An InputStream that can be used to retrieve the contents of the file.
      Throws:
      IOException - if an error occurs.

    • getName

      public String getName()
      Gets the original file name in the client's file system.
      Specified by:
      getName in interface FileItem
      Returns:
      The original file name in the client's file system.
      Throws:
      InvalidFileNameException - The file name contains a NUL character, which might be an indicator of a security attack. If you intend to use the file name anyways, catch the exception and use InvalidFileNameException.getName().

    • getOutputStream

      public OutputStream getOutputStream() throws IOException
      Gets an OutputStream that can be used for storing the contents of the file.
      Specified by:
      getOutputStream in interface FileItem
      Returns:
      An OutputStream that can be used for storing the contents of the file.
      Throws:
      IOException - if an error occurs (never happens).

    • getSize

      public long getSize()
      Gets the size of the file.
      Specified by:
      getSize in interface FileItem
      Returns:
      The size of the file, in bytes.

    • getStoreLocation

      public File getStoreLocation()
      Gets the File object 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 File.renameTo(java.io.File) 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
      Returns:
      The contents of the file, as a string.

    • getString

      public String getString(String charset) throws UnsupportedEncodingException
      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
      Parameters:
      charset - The charset to use.
      Returns:
      The contents of the file, as a string.
      Throws:
      UnsupportedEncodingException - if the requested character encoding is not available.

    • getTempFile

      protected File 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
      Returns:
      true if the instance represents a simple form field; false if it represents an uploaded file.
      See Also:

    • 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
      Returns:
      true if the file contents will be read from memory; false otherwise.

    • setDefaultCharset

      public void setDefaultCharset(String charset)
      Sets the default charset for use when no explicit charset parameter is provided by the sender.
      Parameters:
      charset - the default charset

    • setFieldName

      public void setFieldName(String fieldName)
      Sets the field name used to reference this file item.
      Specified by:
      setFieldName in interface FileItem
      Parameters:
      fieldName - The name of the form field.
      See Also:

    • setFormField

      public void setFormField(boolean formField)
      Sets whether or not a FileItem instance represents a simple form field.
      Specified by:
      setFormField in interface FileItem
      Parameters:
      formField - true if the instance represents a simple form field; false if it represents an uploaded file.
      See Also:

    • setHeaders

      public void setHeaders(FileItemHeaders headers)
      Sets the file item headers.
      Specified by:
      setHeaders in interface FileItemHeadersSupport
      Parameters:
      headers - The file items headers.

    • 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 void write(File file) throws Exception
      A convenience method to write 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
      Parameters:
      file - The File into which the uploaded item should be stored.
      Throws:
      Exception - if an error occurs.