Spring WebClient。 接收多部分/表单数据

Question

There is existing BodyExtractors for multipart/form-data for using with WebClient.

I found:

1. Solution to send multipart/form-data via WebClient;
2. Solution to read multipart/form-data in Controllers. ( BodyExtractors.toMultipartData() )

But I can't find the solution to parse multipart response body by WebClient.

Answer 1

You must register it as a custom codec directly with the WebClient .

For example, in your WebClient bean:

return WebClient.builder()
        .codecs(clientCodecConfigurer -> clientCodecConfigurer.defaultCodecs().maxInMemorySize(1 * 1024 * 1024)) // How to change defaults
        .codecs(clientCodecConfigurer -> clientCodecConfigurer.customCodecs()
            .register(new MultipartHttpMessageReader(new DefaultPartHttpMessageReader())) // <-- Add this custom codec
        )
        .defaultHeader(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE) // How to set default header
        .baseUrl("https://foo.local") // How to set Base URL in builder
        .build();

This registers the MultipartHttpMessageReader for this WebClient .

If you only have a WebClient instance prefabricated, you can still mutate it:

MultiValueMap<String, Part> response = webClient
  .mutate() // This creates a pre-initialized builder
  .codecs(clientCodecConfigurer -> clientCodecConfigurer.customCodecs()
      .register(new MultipartHttpMessageReader(new DefaultPartHttpMessageReader())) // <-- Add our codec
  )
  .build() // Build a new instance
  .get() // Whatever is your HTTP method
  .accept(MediaType.MULTIPART_FORM_DATA)
  .retrieve()
  .bodyToMono(new ParameterizedTypeReference<MultiValueMap<String, Part>>() { 
      /* Freeze generic types. You need the exact type, as the Codec looks into the key and value types as well. */ 
  })
  .block();

This way, you can keep the values from the previous builder (eg, OAuth2 filters).