org.apache.commons.fileupload.disk
Class DiskFileItem

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

All Implemented Interfaces:

Serializable, FileItem, FileItemHeadersSupport

Direct Known Subclasses:

DefaultFileItem

public class DiskFileItem
extends 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.

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 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 963609 2010-07-13 06:56:47Z jochen $

Author:

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

See Also:

Serialized Form

Field Summary

static String

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

Constructor Summary

DiskFileItem(String fieldName, String contentType, boolean isFormField, String fileName, int sizeThreshold, 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.
String	getCharSet() Returns the content charset passed by the agent or null if not defined.
String	getContentType() Returns the content type passed by the agent or null if not defined.
String	getFieldName() Returns the name of the field in the multipart form corresponding to this file item.
FileItemHeaders	getHeaders() Returns the file item headers.
InputStream	getInputStream() Returns an InputStream that can be used to retrieve the contents of the file.
String	getName() Returns the original filename in the client's filesystem.
OutputStream	getOutputStream() Returns an OutputStream that can be used for storing the contents of the file.
long	getSize() Returns the size of the file.
File	getStoreLocation() Returns the File object for the FileItem's data's temporary location on the disk.
String	getString() Returns the contents of the file as a String, using the default character encoding.
String	getString(String charset) Returns 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.
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.
void	setFieldName(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.
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 Detail

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:

Constant Field Values

Constructor Detail

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 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 InputStream getInputStream()
                           throws 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:

IOException - if an error occurs.

getContentType

public 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 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 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.

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().

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 String getString(String charset)
                 throws 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:

UnsupportedEncodingException - if the requested character encoding is not available.

getString

public 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(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.

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 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(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 OutputStream getOutputStream()
                             throws 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:

IOException - if an error occurs.

getStoreLocation

public 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 Object

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.

Returns:

The File to be used for temporary storage.

toString

public String toString()

Returns a string representation of this object.

Overrides:

toString in class Object

Returns:

a string representation of this object.

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.