https://javaee.github.io/servlet-spec/: Java.net - The Source for Java Technology Collaboration (GlassFish Community) 
/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2017 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://oss.oracle.com/licenses/CDDL+GPL-1.1
 * or LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package javax.servlet.http;

import java.io.*;
import java.util.*;


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

Since:Servlet 3.0
/**
 * <p> This class represents a part or form item that was received within a
 * <code>multipart/form-data</code> POST request.
 * 
 * @since Servlet 3.0
 */
public interface Part {

    
Gets the content of this part as an InputStream

Throws:
  • IOException – If an error occurs in retrieving the content
as an InputStream
Returns:The content of this part as an InputStream
/**
     * Gets the content of this part as an <tt>InputStream</tt>
     * 
     * @return The content of this part as an <tt>InputStream</tt>
     * @throws IOException If an error occurs in retrieving the content
     * as an <tt>InputStream</tt>
     */
    public InputStream getInputStream() throws IOException;

    
Gets the content type of this part.

Returns:The content type of this part.
/**
     * Gets the content type of this part.
     *
     * @return The content type of this part.
     */
    public String getContentType();

    
Gets the name of this part

Returns:The name of this part as a String
/**
     * Gets the name of this part
     *
     * @return The name of this part as a <tt>String</tt>
     */
    public String getName();

    
Gets the file name specified by the client

Returns:the submitted file name
Since:Servlet 3.1
/**
     * Gets the file name specified by the client
     *
     * @return the submitted file name
     *
     * @since Servlet 3.1
     */
    public String getSubmittedFileName();

    
Returns the size of this fille.

Returns:a long specifying the size of this part, in bytes.
/**
     * Returns the size of this fille.
     *
     * @return a <code>long</code> specifying the size of this part, in bytes.
     */
    public long getSize();

    
A convenience method to write this uploaded item to disk.

This method is not guaranteed to succeed if called more than once for
the same part. 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.

Params:
  • fileName – The location into which the uploaded part should be stored. The value may be a file name or a path. The actual location of the file in the filesystem is relative to MultipartConfigElement.getLocation(). Absolute paths are used as provided and are relative to getLocation().  Note: that this is a system
dependent string and URI notation may not be acceptable on all
systems. For portability, this string should be generated with
the File or Path APIs.
Throws:
/**
     * A convenience method to write this uploaded item to disk.
     * 
     * <p>This method is not guaranteed to succeed if called more than once for
     * the same part. 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.
     *
     * @param fileName The location into which the uploaded part should
       be stored. The value may be a file name or a path.  The actual
       location of the file in the filesystem is relative to {@link
       javax.servlet.MultipartConfigElement#getLocation()}.  Absolute
       paths are used as provided and are relative to
       <code>getLocation()</code>.  Note: that this is a system
       dependent string and URI notation may not be acceptable on all
       systems. For portability, this string should be generated with
       the File or Path APIs.
     *
     * @throws IOException if an error occurs.
     */
    public void write(String fileName) throws IOException;

    
Deletes the underlying storage for a file item, including deleting any
associated temporary disk file.

Throws:
  • IOException – if an error occurs.
/**
     * Deletes the underlying storage for a file item, including deleting any
     * associated temporary disk file.
     *
     * @throws IOException if an error occurs.
     */
    public void delete() throws IOException;

    
Returns the value of the specified mime header
as a String. If the Part did not include a header
of the specified name, this method returns null.
If there are multiple headers with the same name, this method
returns the first header in the part.
The header name is case insensitive. You can use
this method with any request header.

Params:
  • name – 		a String specifying the
			header name
Returns:			a String containing the
			value of the requested
			header, or null
			if the part does not
			have a header of that name
/**
     *
     * Returns the value of the specified mime header
     * as a <code>String</code>. If the Part did not include a header
     * of the specified name, this method returns <code>null</code>.
     * If there are multiple headers with the same name, this method
     * returns the first header in the part.
     * The header name is case insensitive. You can use
     * this method with any request header.
     *
     * @param name		a <code>String</code> specifying the
     *				header name
     *
     * @return			a <code>String</code> containing the
     *				value of the requested
     *				header, or <code>null</code>
     *				if the part does not
     *				have a header of that name
     */
    public String getHeader(String name);

    
Gets the values of the Part header with the given name.

Any changes to the returned Collection must not 
affect this Part.

Part header names are case insensitive.

Params:
  • name – the header name whose values to return
Returns:a (possibly empty) Collection of the values of
the header with the given name
/**
     * Gets the values of the Part header with the given name.
     *
     * <p>Any changes to the returned <code>Collection</code> must not 
     * affect this <code>Part</code>.
     *
     * <p>Part header names are case insensitive.
     *
     * @param name the header name whose values to return
     *
     * @return a (possibly empty) <code>Collection</code> of the values of
     * the header with the given name
     */
    public Collection<String> getHeaders(String name);

    
Gets the header names of this Part.

Some servlet containers do not allow
servlets to access headers using this method, in
which case this method returns null

Any changes to the returned Collection must not 
affect this Part.

Returns:a (possibly empty) Collection of the header
names of this Part
/**
     * Gets the header names of this Part.
     *
     * <p>Some servlet containers do not allow
     * servlets to access headers using this method, in
     * which case this method returns <code>null</code>
     *
     * <p>Any changes to the returned <code>Collection</code> must not 
     * affect this <code>Part</code>.
     *
     * @return a (possibly empty) <code>Collection</code> of the header
     * names of this Part
     */
    public Collection<String> getHeaderNames();

}