Question

我遇到了Spring Integration问题。我试图通过HttpRequestExecutingMessageHandler执行rest调用。我的其余端点仅接受内容类型“ application / json”。

问题在于HttpRequestExecutingMessageHandler正在使用内容类型'text / plain; charset = UTF-8'进行发布。

@ServiceActivator(inputChannel = "transformRequestToJsonChannel", 
   outputChannel = "httpRequestOutChannel")
public Message<?> transformRequest(Message<DocumentConverterRequest> 
   message) 
{
  LOG.info("transforming document converter request to json: '{}'",         
  ObjectToJsonTransformer transformer = new ObjectToJsonTransformer();
  transformer.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);
  Object payload = transformer.transform(message).getPayload();
  LOG.info("payload: '{}'", payload.toString());
  return MessageBuilder.withPayload(payload).build();
}

@Bean
@ServiceActivator(inputChannel = "httpRequestOutChannel")
public HttpRequestExecutingMessageHandler outbound() {
  HttpRequestExecutingMessageHandler handler = new 
  HttpRequestExecutingMessageHandler(documentConverterRestUrl);
  handler.setHttpMethod(HttpMethod.POST);
  handler.setErrorHandler(httpResponseErrorHandler);
  handler.setExpectedResponseType(String.class);
  handler.setCharset(Charset.defaultCharset().name());
  HeaderMapper<HttpHeaders> mapper = new DefaultHttpHeaderMapper();
  HttpHeaders httpHeaders = new HttpHeaders();
  httpHeaders.add(HttpHeaders.CONTENT_TYPE, 
    MediaType.APPLICATION_JSON_VALUE);
  mapper.toHeaders(httpHeaders);
  handler.setHeaderMapper(mapper);
  handler.setOutputChannel(httpResponseChannel());
  return handler;
}

如何覆盖内容类型？

Answer 1

这段代码不执行任何操作：

  HeaderMapper<HttpHeaders> mapper = new DefaultHttpHeaderMapper();
  HttpHeaders httpHeaders = new HttpHeaders();
  httpHeaders.add(HttpHeaders.CONTENT_TYPE, 
    MediaType.APPLICATION_JSON_VALUE);
  mapper.toHeaders(httpHeaders);

当我们收到回复时，就会从toHeaders()调用HttpRequestExecutingMessageHandler。在代码中显式使用它真的没用，尤其是在bean定义阶段以及忽略结果时。

您完全不需要使用显式的HeaderMapper：默认值足以满足您的需求。

ObjectToJsonTransformer实际上将setContentType()映射到它所回复的消息的标题中：

if (headers.containsKey(MessageHeaders.CONTENT_TYPE)) {
        // override, unless empty
        if (this.contentTypeExplicitlySet && StringUtils.hasLength(this.contentType)) {
            headers.put(MessageHeaders.CONTENT_TYPE, this.contentType);
        }
}
else if (StringUtils.hasLength(this.contentType)) {
        headers.put(MessageHeaders.CONTENT_TYPE, this.contentType);
}

因此，有一个适当的内容类型可以映射。默认情况下，HttpRequestExecutingMessageHandler使用：

/**
 * Factory method for creating a basic outbound mapper instance.
 * This will map all standard HTTP request headers when sending an HTTP request,
 * and it will map all standard HTTP response headers when receiving an HTTP response.
 * @return The default outbound mapper.
 */
public static DefaultHttpHeaderMapper outboundMapper() {

具有一组适当的标头，以映射到HTTP请求和HTTP响应。

new DefaultHttpHeaderMapper()仅带来一组空白的标头来映射。

请提出一个问题以改进JavaDocs和参考手册，以注意该类的默认ctor不会带来任何标头。

Answer 2

and True or False

我删除了ObjectToJsonTransformer，因为@Bean @ServiceActivator(inputChannel = "httpRequestOutChannel") public HttpRequestExecutingMessageHandler outbound() { HttpRequestExecutingMessageHandler handler = Http.outboundGateway(documentConverterRestUrl) .httpMethod(HttpMethod.POST) .messageConverters(new MappingJackson2HttpMessageConverter()) .mappedRequestHeaders("Content-Type") .get(); handler.setOutputChannel(httpResponseChannel()); return handler; }在做这些事情。

我还必须将messageConverters(new MappingJackson2HttpMessageConverter())添加到我的消息标题中：content-type

Spring Integration HttpRequestExecutingMessageHandler ContentType问题

2 个答案: