org.apache.commons.fileupload
Interface FileItem

All Superinterfaces:

Serializable

All Known Implementing Classes:

DefaultFileItem, DiskFileItem

public interface FileItem
extends Serializable

This class represents a file or form item that was received within a multipart/form-data POST request.

After retrieving an instance of this class from a FileUpload instance (see #parseRequest(javax.servlet.http.HttpServletRequest)), you may either request all contents of the 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.

While this interface does not extend javax.activation.DataSource per se (to avoid a seldom used dependency), several of the defined methods are specifically defined with the same signatures as methods in that interface. This allows an implementation of this interface to also implement javax.activation.DataSource with minimal additional work.

Version:

$Id: FileItem.java 963609 2010-07-13 06:56:47Z jochen $

Author:

Rafal Krzewski, Sean Legassick, Jason van Zyl, Martin Cooper

Method Summary

void	delete() Deletes the underlying storage for a file item, including deleting any associated temporary disk file.
byte[]	get() Returns the contents of the file item as an array of bytes.
String	getContentType() Returns the content type passed by the browser or null if not defined.
String	getFieldName() Returns the name of the field in the multipart form corresponding to this file item.
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, as provided by the browser (or other client software).
OutputStream	getOutputStream() Returns an OutputStream that can be used for storing the contents of the file.
long	getSize() Returns the size of the file item.
String	getString() Returns the contents of the file item as a String, using the default character encoding.
String	getString(String encoding) Returns the contents of the file item as a String, using the specified encoding.
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 name) 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	write(File file) A convenience method to write an uploaded item to disk.

Method Detail

getInputStream

InputStream getInputStream()
                           throws IOException

Returns an InputStream that can be used to retrieve the contents of the file.

Returns:

An InputStream that can be used to retrieve the contents of the file.

Throws:

IOException - if an error occurs.

getContentType

String getContentType()

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

Returns:

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

getName

String getName()

Returns the original filename in the client's filesystem, as provided by the browser (or other client software). In most cases, this will be the base file name, without path information. However, some clients, such as the Opera browser, do include path information.

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

boolean isInMemory()

Provides a hint as to whether or not the file contents will be read from memory.

Returns:

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

getSize

long getSize()

Returns the size of the file item.

Returns:

The size of the file item, in bytes.

get

byte[] get()

Returns the contents of the file item as an array of bytes.

Returns:

The contents of the file item as an array of bytes.

getString

String getString(String encoding)
                 throws UnsupportedEncodingException

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

Parameters:

encoding - The character encoding to use.

Returns:

The contents of the item, as a string.

Throws:

UnsupportedEncodingException - if the requested character encoding is not available.

getString

String getString()

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

Returns:

The contents of the item, as a string.

write

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 method is not guaranteed to succeed if called more than once for the same item. This allows a particular implementation to use, for example, file renaming, where possible, rather than copying all of the underlying data, thus gaining a significant performance benefit.

Parameters:

file - The File into which the uploaded item should be stored.

Throws:

Exception - if an error occurs.

delete

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.

getFieldName

String getFieldName()

Returns the name of the field in the multipart form corresponding to this file item.

Returns:

The name of the form field.

setFieldName

void setFieldName(String name)

Sets the field name used to reference this file item.

Parameters:

name - The name of the form field.

isFormField

boolean isFormField()

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

Returns:

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

setFormField

void setFormField(boolean state)

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

Parameters:

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

getOutputStream

OutputStream getOutputStream()
                             throws IOException

Returns an OutputStream that can be used for storing the contents of the file.

Returns:

An OutputStream that can be used for storing the contensts of the file.

Throws:

IOException - if an error occurs.