org.apache.commons.fileupload
Interface FileItem

All Superinterfaces:
java.io.Serializable
All Known Implementing Classes:
DefaultFileItem

public interface FileItem
extends java.io.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 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,v 1.11 2002/12/25 04:05:07 martinc Exp $
Author:
Rafal Krzewski, Sean Legassick, Jason van Zyl, Martin Cooper

Field Summary
static int DEFAULT_UPLOAD_SIZE_THRESHOLD
          The maximal size of request that will have it's elements stored in memory.
 
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 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.
 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(java.lang.String name)
          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.
 

Field Detail

DEFAULT_UPLOAD_SIZE_THRESHOLD

public static final int DEFAULT_UPLOAD_SIZE_THRESHOLD
The maximal size of request that will have it's elements stored in memory.
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.
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.
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.
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.
Returns:
true if the file contents will be read from memory.

getSize

public long getSize()
Returns the size of the file.
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.
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.
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.
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.
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.
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.

getFieldName

public java.lang.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

public void setFieldName(java.lang.String name)
Sets the field name used to reference this file item.
Parameters:
name - The name of the form field.

isFormField

public 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.

setIsFormField

public void setIsFormField(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

public java.io.OutputStream getOutputStream()
                                     throws java.io.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:
java.io.IOException - if an error occurs.