https://tomcat.apache.org/: javax.servlet package 
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package javax.servlet.http;

import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;


This class represents a part as uploaded to the server as part of a
multipart/form-data request body. The part may represent either
an uploaded file or form data.

Since:Servlet 3.0
/**
 * This class represents a part as uploaded to the server as part of a
 * <code>multipart/form-data</code> request body. The part may represent either
 * an uploaded file or form data.
 *
 * @since Servlet 3.0
 */
public interface Part {

    
Obtain an InputStream that can be used to retrieve the
contents of the file.

Throws:
  • IOException – if an I/O occurs while obtaining the stream
Returns:An InputStream for the contents of the file
/**
     * Obtain an <code>InputStream</code> that can be used to retrieve the
     * contents of the file.
     *
     * @return An InputStream for the contents of the file
     *
     * @throws IOException if an I/O occurs while obtaining the stream
     */
    public InputStream getInputStream() throws IOException;

    
Obtain the content type passed by the browser.

Returns:The content type passed by the browser or null if
        not defined.
/**
     * Obtain the content type passed by the browser.
     *
     * @return The content type passed by the browser or <code>null</code> if
     *         not defined.
     */
    public String getContentType();

    
Obtain the name of the field in the multipart form corresponding to this
part.

Returns:The name of the field in the multipart form corresponding to this
        part.
/**
     * Obtain the name of the field in the multipart form corresponding to this
     * part.
     *
     * @return The name of the field in the multipart form corresponding to this
     *         part.
     */
    public String getName();

    
If this part represents an uploaded file, gets the file name submitted in the upload. Returns null if no file name is available or if this part is not a file upload. 
Returns:the submitted file name or null.
Since:Servlet 3.1
/**
     * If this part represents an uploaded file, gets the file name submitted
     * in the upload. Returns {@code null} if no file name is available or if
     * this part is not a file upload.
     *
     * @return the submitted file name or {@code null}.
     *
     * @since Servlet 3.1
     */
    public String getSubmittedFileName();

    
Obtain the size of this part.

Returns:The size of the part if bytes
/**
     * Obtain the size of this part.
     *
     * @return The size of the part if bytes
     */
    public long getSize();

    
A convenience method to write an uploaded part to disk. The client code
is not concerned with whether or not the part is stored in memory, or on
disk in a temporary location. They just want to write the uploaded part
to a file.
 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:
Throws:
  • IOException – if an I/O occurs while attempting to write the part
/**
     * A convenience method to write an uploaded part to disk. The client code
     * is not concerned with whether or not the part is stored in memory, or on
     * disk in a temporary location. They just want to write the uploaded part
     * to a file.
     *
     *  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. Relative locations are relative to {@link
     *                  javax.servlet.MultipartConfigElement#getLocation()}
     *
     * @throws IOException if an I/O occurs while attempting to write the part
     */
    public void write(String fileName) throws IOException;

    
Deletes the underlying storage for a part, including deleting any
associated temporary disk file. Although the container will delete this
storage automatically this method can be used to ensure that this is done
at an earlier time, thus preserving system resources.


Containers are only required to delete the associated storage when the
Part instance is garbage collected. Apache Tomcat will delete the
associated storage when the associated request has finished processing.
Behaviour of other containers may be different.

Throws:
  • IOException – if an I/O occurs while attempting to delete the part
/**
     * Deletes the underlying storage for a part, including deleting any
     * associated temporary disk file. Although the container will delete this
     * storage automatically this method can be used to ensure that this is done
     * at an earlier time, thus preserving system resources.
     * <p>
     * Containers are only required to delete the associated storage when the
     * Part instance is garbage collected. Apache Tomcat will delete the
     * associated storage when the associated request has finished processing.
     * Behaviour of other containers may be different.
     *
     * @throws IOException if an I/O occurs while attempting to delete the part
     */
    public void delete() throws IOException;

    
Obtains the value of the specified part header as a String. If there are
multiple headers with the same name, this method returns the first header
in the part. The header name is case insensitive.

Params:
  • name –  Header name
Returns:     The header value or null if the header is not
             present
/**
     * Obtains the value of the specified part header as a String. If there are
     * multiple headers with the same name, this method returns the first header
     * in the part. The header name is case insensitive.
     *
     * @param name  Header name
     * @return      The header value or <code>null</code> if the header is not
     *              present
     */
    public String getHeader(String name);

    
Obtain all the values of the specified part header.

Params:
  • name – The name of the header of interest. The header name is case
            insensitive.
Returns:All the values of the specified part header. If the part did not
        include any headers of the specified name, this method returns an
        empty Collection.
/**
     * Obtain all the values of the specified part header.
     * @param name The name of the header of interest. The header name is case
     *             insensitive.
     * @return All the values of the specified part header. If the part did not
     *         include any headers of the specified name, this method returns an
     *         empty Collection.
     */
    public Collection<String> getHeaders(String name);

    
Get the header names provided for this part.

Returns:a Collection of all the header names provided for this part.
/**
     * Get the header names provided for this part.
     * @return a Collection of all the header names provided for this part.
     */
    public Collection<String> getHeaderNames();
}