org.apache.commons.fileupload

Class DefaultFileItem

Implemented Interfaces:
FileItem, Serializable

public class DefaultFileItem
extends java.lang.Object
implements FileItem

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.

Version:
$Id: DefaultFileItem.java,v 1.21 2003/06/24 05:45:15 martinc Exp $

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

Nested Class Summary

Field Summary

private byte[]
cachedContent
Cached contents of the file.
private String
contentType
The content type passed by the browser, or null if not defined.
private static int
counter
Counter used in unique identifier generation.
private DeferredFileOutputStream
dfos
Output stream for this item.
private String
fieldName
The name of the form field as provided by the browser.
private String
fileName
The original filename in the user's filesystem.
private boolean
isFormField
Whether or not this item is a simple form field.
private File
repository
The directory in which uploaded files will be stored, if stored on disk.
private int
sizeThreshold
The threshold above which uploads will be stored on disk.

Constructor Summary

DefaultFileItem(String fieldName, String contentType, boolean isFormField, String fileName, int sizeThreshold, File repository)
Constructs a new DefaultFileItem 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
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.
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 java.io.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 encoding)
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.
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 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.
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
write(File file)
A convenience method to write an uploaded item to disk.

Field Details

cachedContent

private byte[] cachedContent
Cached contents of the file.


contentType

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


counter

private static int counter
Counter used in unique identifier generation.


dfos

private DeferredFileOutputStream dfos
Output stream for this item.


fieldName

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


fileName

private String fileName
The original filename in the user's filesystem.


isFormField

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


repository

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


sizeThreshold

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

Constructor Details

DefaultFileItem

(package private)  DefaultFileItem(String fieldName,
                                   String contentType,
                                   boolean isFormField,
                                   String fileName,
                                   int sizeThreshold,
                                   File repository)
Constructs a new DefaultFileItem 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 Details

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()
Removes the file contents from the temporary storage.


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.


getContentType

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

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


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)


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.


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.


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.


getSize

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

Returns:
The size of the file, in bytes.


getStoreLocation

public File getStoreLocation()
Returns the java.io.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 java.io.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()
Specified by:
getString in interface FileItem

Returns:
The contents of the file, as a string.


getString

public String getString(String encoding)
            throws UnsupportedEncodingException
Specified by:
getString in interface FileItem

Parameters:
encoding - The character encoding to use.

Returns:
The contents of the file, as a string.


getTempFile

protected File getTempFile()
Creates and returns a File representing a uniquely named temporary file in the configured repository path.

Returns:
The File to be used for temporary storage.


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 apearance.

Returns:
A String with the non-random looking instance identifier.


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)


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.


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()


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()


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.


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