Spring Cloud Feign调用WebService无法提取含CID的二进制数据求助

问题根源是你的自定义SOAPDecoder未处理MTOM/XOP格式的附件解析，响应中xop:Include标签指向的cid对应MIME附件，但解码器没有将cid映射为实际二进制数据，导致_return字段为空。以下是具体解决步骤：

• 启用Feign客户端的MTOM支持
  集成支持MTOM的SOAP消息工厂，比如Spring WS的SaajSoapMessageFactory，开启MTOM后才能解析MIME附件：

  @Bean
  public SaajSoapMessageFactory soapMessageFactory() {
      SaajSoapMessageFactory factory = new SaajSoapMessageFactory();
      factory.setMtomEnabled(true);
      return factory;
  }
  

  将该工厂注入自定义SOAPDecoder，让解码器具备MTOM处理能力。

• 修改自定义SOAPDecoder，添加XOP附件解析逻辑
  原解码器仅解析SOAP Body的XML结构，需补充cid到二进制数据的映射逻辑。示例代码（基于Spring WS）：

  public class CustomMTOMSOAPDecoder extends SOAPDecoder {
      private final SaajSoapMessageFactory messageFactory;
  
      public CustomMTOMSOAPDecoder(SaajSoapMessageFactory messageFactory) {
          this.messageFactory = messageFactory;
      }
  
      @Override
      public Object decode(Response response, Type type) throws IOException, DecodeException {
          // 将响应流转换为SOAP消息
          InputStream inputStream = response.body().asInputStream();
          SoapMessage soapMessage = messageFactory.createWebServiceMessage(inputStream);
  
          // 定位所有xop:Include节点
          Document document = soapMessage.getDocument();
          XPath xpath = XPathFactory.newInstance().newXPath();
          xpath.setNamespaceContext(new NamespaceContext() {
              @Override
              public String getNamespaceURI(String prefix) {
                  return "xop".equals(prefix) ? "http://www.w3.org/2004/08/xop/include" : XMLConstants.NULL_NS_URI;
              }
  
              @Override
              public String getPrefix(String namespaceURI) { return null; }
              @Override
              public Iterator<?> getPrefixes(String namespaceURI) { return null; }
          });
  
          NodeList includeNodes = (NodeList) xpath.evaluate("//xop:Include", document, XPathConstants.NODESET);
          for (int i = 0; i < includeNodes.getLength(); i++) {
              Element includeElement = (Element) includeNodes.item(i);
              String cid = includeElement.getAttribute("href").replace("cid:", "");
              // 根据cid获取对应附件
              Attachment attachment = soapMessage.getAttachment(cid);
              if (attachment != null) {
                  byte[] binaryData = FileCopyUtils.copyToByteArray(attachment.getInputStream());
                  // 将二进制数据替换xop节点内容（若JAXB接受Base64则编码，否则直接处理字节数组）
                  includeElement.setTextContent(Base64.getEncoder().encodeToString(binaryData));
              }
          }
  
          // 反序列化修改后的XML为AttachmentResponse
          JAXBContext jaxbContext = JAXBContext.newInstance(AttachmentResponse.class);
          Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
          return unmarshaller.unmarshal(new DOMSource(document));
      }
  }
  

  注意：需确保AttachmentResponse的_return字段对应的JAXB注解正确（如@XmlElement(name = "return")），且类型支持二进制数据（如byte[]）。

• 配置Feign请求头，指定MTOM格式
  在PersonProxy接口方法中添加请求头，告知服务端返回MTOM格式响应：

  @FeignClient(name = "personService", url = "${third-party.ws.url}", configuration = FeignMTOMConfig.class)
  public interface PersonProxy {
      @PostMapping(value = "/ws/person", consumes = "application/xop+xml", produces = "application/xop+xml")
      @Headers({
          "Content-Type: application/xop+xml; charset=utf-8; type=\"text/xml\"",
          "Accept: application/xop+xml; charset=utf-8; type=\"text/xml\""
      })
      AttachmentResponse getAttachment();
  }
  

• 验证附件解析逻辑
  调试时可打印soapMessage.getAttachments()确认cid对应的附件存在，同时检查JAXB生成类的字段映射是否正确，确保二进制数据能正确注入_return字段。

内容的提问来源于stack exchange，提问作者Rohit yadav