org.apache.commons.fileupload
Class DefaultFileItem

java.lang.Object
  |
  +--org.apache.commons.fileupload.DefaultFileItem
All Implemented Interfaces:
FileItem, java.io.Serializable

public class DefaultFileItem
extends java.lang.Object
implements FileItem

The default mplementation of the FileItem interface.

After retrieving an instance of this class from a FileUpload 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 1.14 2002/12/25 04:05:07 martinc Exp $
Author:
Rafal Krzewski, Sean Legassick, Jason van Zyl, John McNally, Martin Cooper
See Also:
Serialized Form

Field Summary
private  java.io.ByteArrayOutputStream byteStream
          Temporary storage for in-memory files.
private  byte[] content
          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.
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  boolean isFormField
          Whether or not this item is a simple form field.
private  java.io.File storeLocation
          Temporary storage location on disk.
 
Fields inherited from interface org.apache.commons.fileupload.FileItem
DEFAULT_UPLOAD_SIZE_THRESHOLD
 
Constructor Summary
  DefaultFileItem()
          Default constructor.
protected DefaultFileItem(java.lang.String fileName, java.lang.String contentType)
          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.
 java.lang.String getContentType()
          Returns the content type passed by the browser or null if not defined.
 java.lang.String getFieldName()
          Returns the name of the field in the multipart form corresponding to this file item.
 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 encoding)
          Returns the contents of the file as a String, using the specified encoding.
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.
static FileItem newInstance(java.lang.String path, java.lang.String name, java.lang.String contentType, int requestSize, int threshold)
          Instantiates a DefaultFileItem.
 void setFieldName(java.lang.String fieldName)
          Sets the field name used to reference this file item.
 void setIsFormField(boolean state)
          Specifies whether or not a FileItem instance represents a simple form field.
 void write(java.lang.String file)
          A convenience method to write an uploaded file to disk.
 
Methods inherited from class java.lang.Object
, clone, equals, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait
 

Field Detail

counter

private static int counter
Counter used in unique identifier generation.

fileName

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

contentType

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

content

private byte[] content
Cached contents of the file.

storeLocation

private java.io.File storeLocation
Temporary storage location on disk.

byteStream

private java.io.ByteArrayOutputStream byteStream
Temporary storage for in-memory files.

fieldName

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

isFormField

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

DefaultFileItem

public DefaultFileItem()
Default constructor.

DefaultFileItem

protected DefaultFileItem(java.lang.String fileName,
                          java.lang.String contentType)
Constructs a new DefaultFileItem instance.

Use newInstance(String,String,String,int,int) to instantiate DefaultFileItems.

Parameters:
fileName - The original filename in the user's filesystem.
contentType - The content type passed by the browser or null if not defined.
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 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.

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.

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 encoding)
                           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:
encoding - The character encoding 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.

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(File) to move the file to new location without copying the data, if the source and destination locations reside within the same logical volume.
Specified by:
getStoreLocation in interface FileItem
Returns:
The data file, or null if the data is stored in memory.

write

public void write(java.lang.String file)
           throws java.lang.Exception
A convenience method to write an uploaded file to disk. The client code is not concerned whether or not the file is stored in memory, or on disk in a temporary location. They just want to write the uploaded file to disk.
Specified by:
write in interface FileItem
Parameters:
file - The full path to location where the uploaded file 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.

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.

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.

setIsFormField

public void setIsFormField(boolean state)
Specifies whether or not a FileItem instance represents a simple form field.
Specified by:
setIsFormField in interface FileItem
Parameters:
state - true if the instance represents a simple form field; false if it represents an uploaded file.

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.

finalize

protected void finalize()
Removes the file contents from the temporary storage.
Overrides:
finalize in class java.lang.Object

newInstance

public static FileItem newInstance(java.lang.String path,
                                   java.lang.String name,
                                   java.lang.String contentType,
                                   int requestSize,
                                   int threshold)
Instantiates a DefaultFileItem. It uses requestSize to decide what temporary storage approach the new item should take.
Parameters:
path - The path under which temporary files should be created.
name - The original filename in the client's filesystem.
contentType - The content type passed by the browser, or null if not defined.
requestSize - The total size of the POST request this item belongs to.
threshold - The maximum size to store in memory.
Returns:
A DefaultFileItem instance.

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.