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 java.lang.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 and Description
static java.lang.String	DEFAULT_CHARSET Default content charset to be used when no explicit charset parameter is provided by the sender.

Constructor Summary

Constructors

Constructor and Description
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

Modifier and Type	Method and Description
void	delete() Deletes the underlying storage for a file item, including deleting any associated temporary disk file.
byte[]	get() Gets the contents of the file as an array of bytes.
java.lang.String	getCharSet() Gets the content charset passed by the agent or null if not defined.
java.lang.String	getContentType() Gets the content type passed by the agent or null if not defined.
java.lang.String	getDefaultCharset() Gets the default charset for use when no explicit charset parameter is provided by the sender.
java.lang.String	getFieldName() Gets the name of the field in the multipart form corresponding to this file item.
FileItemHeaders	getHeaders() Gets the file item headers.
java.io.InputStream	getInputStream() Gets an InputStream that can be used to retrieve the contents of the file.
java.lang.String	getName() Gets the original file name in the client's file system.
java.io.OutputStream	getOutputStream() Gets an OutputStream that can be used for storing the contents of the file.
long	getSize() Gets the size of the file.
java.io.File	getStoreLocation() Gets the File object for the FileItem's data's temporary location on the disk.
java.lang.String	getString() Gets the contents of the file as a String, using the default character encoding.
java.lang.String	getString(java.lang.String charset) Gets the contents of the file as a String, using the specified encoding.
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(java.lang.String charset) Sets the default charset for use when no explicit charset parameter is provided by the sender.
void	setFieldName(java.lang.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.
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.

Methods inherited from class java.lang.Object

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

Field Detail

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

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 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 Detail

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

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:

java.io.UncheckedIOException - if an I/O error occurs.

java.lang.OutOfMemoryError - if an array of the required size cannot be allocated, for example the file is larger that 2GB.

getCharSet

public java.lang.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 java.lang.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 java.lang.String getDefaultCharset()

Gets the default charset for use when no explicit charset parameter is provided by the sender.

Returns:

the default charset

getFieldName

public java.lang.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:

setFieldName(String)

getHeaders

public FileItemHeaders getHeaders()

Gets the file item headers.

Specified by:

getHeaders in interface FileItemHeadersSupport

Returns:

The file items headers.

getInputStream

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

java.io.IOException - if an error occurs.

getName

public java.lang.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 java.io.OutputStream getOutputStream()
                                     throws java.io.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:

java.io.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 java.io.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 java.lang.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 java.lang.String getString(java.lang.String charset)
                           throws java.io.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:

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

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:

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

Returns:

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

setDefaultCharset

public void setDefaultCharset(java.lang.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(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()

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:

isFormField()

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 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.

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.