Package org.apache.commons.fileupload2.core

Class MultipartInput

  • public final class MultipartInput
extends Object
    Low-level API for processing file uploads.

    This class can be used to process data streams conforming to MIME 'multipart' format as defined in RFC 1867. Arbitrarily large amounts of data in the stream can be processed under constant memory usage.

    The format of the stream is defined in the following way:

    multipart-body := preamble 1*encapsulation close-delimiter epilogue
    encapsulation := delimiter body CRLF
    delimiter := "--" boundary CRLF
    close-delimiter := "--" boundary "--"
    preamble := <ignore>
    epilogue := <ignore>
    body := header-part CRLF body-part
    header-part := 1*header CRLF
    header := header-name ":" header-value
    header-name := <printable ascii characters except ":">
    header-value := <any ascii characters except CR & LF>
    body-data := <arbitrary data>

    Note that body-data can contain another mulipart entity. There is limited support for single pass processing of such nested streams. The nested stream is required to have a boundary token of the same length as the parent stream (see setBoundary(byte[])).

    Here is an example of usage of this class: 

     try {
     MultipartInput multipartStream = new MultipartInput(input, boundary);
     boolean nextPart = multipartStream.skipPreamble();
     OutputStream output;
     while (nextPart) {
         String header = multipartStream.readHeaders();
         // process headers
         // create some output stream
         multipartStream.readBodyData(output);
         nextPart = multipartStream.readBoundary();
     }
 } catch (MultipartInput.MalformedStreamException e) {
     // the stream failed to follow required syntax
 } catch (IOException e) {
     // a read or write error occurred
 }