parse multipart/form-data response in spring

I need to receive multipart/form-data response
but i have no idea on how to parse this kind of response

For example

--mf8sckatxs4PpMnOLF6ltSv26ZJc5qxy9qq
Content-Disposition: form-data; name="arguments"
Content-Type: text/plain;charset=UTF-8
Content-Length: 311
[{"code":200,"message":"123"}]

Content-Disposition: form-data; name="_0"; filename="0_BODY_feature"
Content-Type: application/octet-stream
Content-Length: 407 
binarydata

Since you're using Spring you already have the Apache fileupload and http classes available. MultipartStream is designed to be attached to an incoming byte stream and can provide progress updates as data arrives.

This simple example illustrates a non-streaming scenario where you've already buffered the whole incoming body.

byte[] yourResponse = ... // the whole response as a byte array
String yourContentType = ... // the Content-Type header string

ContentType contentType = ContentType.parse(yourContentType);

MultipartStream multipartStream = new MultipartStream(
  new ByteArrayInputStream(yourResponse),
  contentType.getParameter("boundary").getBytes(), 
  1024,    // internal buffer size (you choose)
  null);   // progress indicator (none)

boolean nextPart = multipartStream.skipPreamble();
while (nextPart) {

  ByteArrayOutputStream output = new ByteArrayOutputStream();
  String partHeaders = multipartStream.readHeaders();
  multipartStream.readBodyData(output);

  // do something with the multi-line part headers
  // do something with the part 'output' byte array

  nextPart = multipartStream.readBoundary();
}

Add exception handling as required.

You can store and separate those values in an Array of Strings:

String[] array = "allyourinputtext".split(";");

This will separate the values after a semicolon. Then, you can access each value by doing this:

String content = array[0];
String name = array[1];
...

This doesn't solve the WHOLE problem(since not all values are separated by semicolons), but you can play with the arguments you pass to split() to separate your values.

Note: If you want to parse a String to int (the length value for example) you can use:

int length = Integer.parseInt(array[index];

My situation: I knew the multipart that I'm receiving is a multivaluemap like this:

> MultiValueMap<String, Resource>

First of all, you need to figure out the boundary.

    String contentTypeHeader = response.getHeaders().getFirst(HttpHeaders.CONTENT_TYPE);
    String boundary = null;

    if (contentTypeHeader != null) {
        MediaType mediaType = MediaType.parseMediaType(contentTypeHeader);
        boundary = mediaType.getParameter("boundary");
    }

Then, make the multipart stream.

MultipartStream multipartStream = new MultipartStream(
            new ByteArrayInputStream(body),
            boundary.getBytes(),
            1024,
            null);

Make a multivaluemap from this multiPartStream

boolean nextPart = multipartStream.skipPreamble();
    while (nextPart) {

        ByteArrayOutputStream output = new ByteArrayOutputStream();
        // Read the headers of the current part.
        // After .readHeaders(), the stream's position will be at the start of the part's body, ready for you to read the part's actual content.
        multipartStream.readHeaders();
        multipartStream.readBodyData(output);

        ByteArrayResource resource = new ByteArrayResource(output.toByteArray());
        multiValueMap.add("file", resource);
        nextPart = multipartStream.readBoundary();
    }
    return multiValueMap;