org.apache.commons.fileupload.disk
Class DiskFileItem

java.lang.Object
  org.apache.commons.fileupload.disk.DiskFileItem

All Implemented Interfaces:

java.io.Serializable, FileItem, FileItemHeadersSupport

Direct Known Subclasses:

DefaultFileItem

public class DiskFileItem
extends java.lang.Object
implements FileItem, FileItemHeadersSupport

The default implementation of the FileItem interface.

After retrieving an instance of this class from a DiskFileUpload 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.

When using the DiskFileItemFactory, then you should 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 automatically when the class FileCleaner is loaded. 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

Version:

$Id: DiskFileItem.java 607869 2008-01-01 16:42:17Z jochen $

Author:

Rafal Krzewski, Sean Legassick, Jason van Zyl, John McNally, Martin Cooper, Sean C. Sullivan

See Also:

Serialized Form

Field Summary

private byte[]	cachedContent Cached contents of the file.
private java.lang.String	contentType The content type passed by the browser, or null if not defined.
private static int	counter Counter used in unique identifier generation.
static java.lang.String	DEFAULT_CHARSET 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 java.io.File	dfosFile File to allow for serialization of the content of this item.
private java.lang.String	fieldName The name of the form field as provided by the browser.
private java.lang.String	fileName The original filename in the user's filesystem.
private FileItemHeaders	headers The file items headers.
private boolean	isFormField Whether or not this item is a simple form field.
private java.io.File	repository The directory in which uploaded files will be stored, if stored on disk.
private static long	serialVersionUID The UID to use when serializing this instance.
private long	size The size of the item, in bytes.
private int	sizeThreshold The threshold above which uploads will be stored on disk.
private java.io.File	tempFile The temporary file to use.
private static java.lang.String	UID UID used in unique file name generation.

Constructor Summary

DiskFileItem(java.lang.String fieldName, java.lang.String contentType, boolean isFormField, java.lang.String fileName, int sizeThreshold, java.io.File repository)
Constructs a new DiskFileItem instance.

Method Summary

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() Returns the contents of the file as an array of bytes.
java.lang.String	getCharSet() Returns the content charset passed by the agent or null if not defined.
java.lang.String	getContentType() Returns the content type passed by the agent or null if not defined.
java.lang.String	getFieldName() Returns the name of the field in the multipart form corresponding to this file item.
FileItemHeaders	getHeaders() Returns the file item headers.
java.io.InputStream	getInputStream() Returns an InputStream that can be used to retrieve the contents of the file.
java.lang.String	getName() Returns the original filename in the client's filesystem.
java.io.OutputStream	getOutputStream() Returns an OutputStream that can be used for storing the contents of the file.
long	getSize() Returns the size of the file.
java.io.File	getStoreLocation() Returns the File object for the FileItem's data's temporary location on the disk.
java.lang.String	getString() Returns the contents of the file as a String, using the default character encoding.
java.lang.String	getString(java.lang.String charset) Returns the contents of the file as a String, using the specified encoding.
protected java.io.File	getTempFile() Creates and returns a File representing a uniquely named temporary file in the configured repository path.
private static java.lang.String	getUniqueId() Returns an identifier that is unique within the class loader used to load this class, but does not have random-like apearance.
boolean	isFormField() Determines 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.
private void	readObject(java.io.ObjectInputStream in) Reads the state of this object during deserialization.
void	setFieldName(java.lang.String fieldName) Sets the field name used to reference this file item.
void	setFormField(boolean state) Specifies whether or not a FileItem instance represents a simple form field.
void	setHeaders(FileItemHeaders pHeaders) Sets the file item headers.
java.lang.String	toString() Returns a string representation of this object.
void	write(java.io.File file) A convenience method to write an uploaded item to disk.
private void	writeObject(java.io.ObjectOutputStream out) Writes the state of this object during serialization.

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

The UID to use when serializing this instance.

See Also:

Constant Field Values

DEFAULT_CHARSET

public static final java.lang.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:

Constant Field Values

UID

private static final java.lang.String UID

UID used in unique file name generation.

counter

private static int counter

Counter used in unique identifier generation.

fieldName

private java.lang.String fieldName

The name of the form field as provided by the browser.

contentType

private java.lang.String contentType

The content type passed by the browser, or null if not defined.

isFormField

private boolean isFormField

Whether or not this item is a simple form field.

fileName

private java.lang.String fileName

The original filename in the user's filesystem.

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 int sizeThreshold

The threshold above which uploads will be stored on disk.

repository

private java.io.File repository

The directory in which uploaded files will be stored, if stored on disk.

cachedContent

private byte[] cachedContent

Cached contents of the file.

dfos

private transient org.apache.commons.io.output.DeferredFileOutputStream dfos

Output stream for this item.

tempFile

private transient java.io.File tempFile

The temporary file to use.

dfosFile

private java.io.File dfosFile

File to allow for serialization of the content of this item.

headers

private FileItemHeaders headers

The file items headers.

Constructor Detail

DiskFileItem

public DiskFileItem(java.lang.String fieldName,
                    java.lang.String contentType,
                    boolean isFormField,
                    java.lang.String fileName,
                    int sizeThreshold,
                    java.io.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 filename in the user's filesystem, 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 Detail

getInputStream

public java.io.InputStream getInputStream()
                                   throws java.io.IOException

Returns 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:

java.io.IOException - if an error occurs.

getContentType

public java.lang.String getContentType()

Returns 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.

getCharSet

public java.lang.String getCharSet()

Returns 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.

getName

public java.lang.String getName()

Returns the original filename in the client's filesystem.

Specified by:

getName in interface FileItem

Returns:

The original filename in the client's filesystem.

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.

getSize

public long getSize()

Returns the size of the file.

Specified by:

getSize in interface FileItem

Returns:

The size of the file, in bytes.

get

public byte[] get()

Returns 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.

getString

public java.lang.String getString(java.lang.String charset)
                           throws java.io.UnsupportedEncodingException

Returns 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:

java.io.UnsupportedEncodingException - if the requested character encoding is not available.

getString

public java.lang.String getString()

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

Specified by:

getString in interface FileItem

Returns:

The contents of the file, as a string.

write

public void write(java.io.File file)
           throws java.lang.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:

java.lang.Exception - if an error occurs.

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

getFieldName

public java.lang.String getFieldName()

Returns 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:

setFieldName(java.lang.String)

setFieldName

public void setFieldName(java.lang.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:

getFieldName()

isFormField

public boolean isFormField()

Determines 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:

setFormField(boolean)

setFormField

public void setFormField(boolean state)

Specifies whether or not a FileItem instance represents a simple form field.

Specified by:

setFormField in interface FileItem

Parameters:

state - true if the instance represents a simple form field; false if it represents an uploaded file.

See Also:

isFormField()

getOutputStream

public java.io.OutputStream getOutputStream()
                                     throws java.io.IOException

Returns 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 contensts of the file.

Throws:

java.io.IOException - if an error occurs.

getStoreLocation

public java.io.File getStoreLocation()

Returns 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.

finalize

protected void finalize()

Removes the file contents from the temporary storage.

Overrides:

finalize in class java.lang.Object

getTempFile

protected java.io.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.

Returns:

The File to be used for temporary storage.

getUniqueId

private static java.lang.String getUniqueId()

Returns an identifier that is unique within the class loader used to load this class, but does not have random-like apearance.

Returns:

A String with the non-random looking instance identifier.

toString

public java.lang.String toString()

Returns a string representation of this object.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of this object.

writeObject

private void writeObject(java.io.ObjectOutputStream out)
                  throws java.io.IOException

Writes the state of this object during serialization.

Parameters:

out - The stream to which the state should be written.

Throws:

java.io.IOException - if an error occurs.

readObject

private void readObject(java.io.ObjectInputStream in)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException

Reads the state of this object during deserialization.

Parameters:

in - The stream from which the state should be read.

Throws:

java.io.IOException - if an error occurs.

java.lang.ClassNotFoundException - if class cannot be found.

getHeaders

public FileItemHeaders getHeaders()

Returns the file item headers.

Specified by:

getHeaders in interface FileItemHeadersSupport

Returns:

The file items headers.

setHeaders

public void setHeaders(FileItemHeaders pHeaders)

Sets the file item headers.

Specified by:

setHeaders in interface FileItemHeadersSupport

Parameters:

pHeaders - The file items headers.