具有 text/html 响应的 Reactive WebClient GET 请求

Question

目前我在使用新的 Spring 5 WebClient 时遇到问题，我需要一些帮助来解决这个问题。问题是：

I request some url that returns json response with content type text/html;charset=utf-8.

But unfortunately I’m still getting an exception: org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'text/html;charset=utf-8' not supported. So I can’t convert response to DTO.

对于请求，我使用以下代码：

Flux<SomeDTO> response = WebClient.create("https://someUrl")
                .get()
                .uri("/someUri").accept(MediaType.APPLICATION_JSON)
                .retrieve()
                .bodyToFlux(SomeDTO.class);

response.subscribe(System.out::println);

顺便说一句，我在 accept header 中指向哪个类型并不重要，总是返回 text/html。那么我怎样才能让我的回复最终得到转换呢？

Answer 1

让服务发送 JSON 和 "text/html" Content-Type 是相当不寻常的。

有两种处理方法：

配置 Jackson 解码器以解码 "text/html" 内容；查看 WebClient.builder().exchangeStrategies(ExchangeStrategies) 设置方法
即时更改 "Content-Type" 响应 header

这是第二种解决方案的建议：

WebClient client = WebClient.builder().filter((request, next) -> next.exchange(request)
                .map(response -> {
                    MyClientHttpResponseDecorator decorated = new 
                        MyClientHttpResponseDecorator(response); 
                    return decorated;
                })).build();

class MyClientHttpResponseDecorator extends ClientHttpResponseDecorator {

  private final HttpHeaders httpHeaders;

  public MyClientHttpResponseDecorator(ClientHttpResponse delegate) {
    super(delegate);
    this.httpHeaders = new HttpHeaders(this.getDelegate().getHeaders());
    // mutate the content-type header when necessary
  }

  @Override
  public HttpHeaders getHeaders() {
    return this.httpHeaders;
  }
}

请注意，您应该只在该上下文中（针对该主机）使用该客户端。如果可以的话，我强烈建议尝试修复服务器返回的奇怪 content-type。

Answer 2

如上一个回答所述，您可以使用 exchangeStrategies 方法，

示例：

            Flux<SomeDTO> response = WebClient.builder()
                .baseUrl(url)
                .exchangeStrategies(ExchangeStrategies.builder().codecs(this::acceptedCodecs).build())
                .build()
                .get()
                .uri(builder.toUriString(), 1L)
                .retrieve()
                .bodyToFlux( // .. business logic


private void acceptedCodecs(ClientCodecConfigurer clientCodecConfigurer) {
    clientCodecConfigurer.customCodecs().encoder(new Jackson2JsonEncoder(new ObjectMapper(), TEXT_HTML));
    clientCodecConfigurer.customCodecs().decoder(new Jackson2JsonDecoder(new ObjectMapper(), TEXT_HTML));
}

Answer 3

如果您需要设置 maxInMemorySize 以及 text/html 响应，请使用：

  WebClient invoicesWebClient() {
    return WebClient.builder()
        .exchangeStrategies(ExchangeStrategies.builder().codecs(this::acceptedCodecs).build())
        .build();
  }

  private void acceptedCodecs(ClientCodecConfigurer clientCodecConfigurer) {
    clientCodecConfigurer.defaultCodecs().maxInMemorySize(BUFFER_SIZE_16MB);
    clientCodecConfigurer.customCodecs().registerWithDefaultConfig(new Jackson2JsonDecoder(new ObjectMapper(), TEXT_HTML));
    clientCodecConfigurer.customCodecs().registerWithDefaultConfig(new Jackson2JsonEncoder(new ObjectMapper(), TEXT_HTML));
  }

具有 text/html 响应的 Reactive WebClient GET 请求

Reactive WebClient GET Request with text/html response

java

spring

reactive

spring-webflux