java - Apache Camel : ProducerTemplate not unmarshalling the response

Question

Camel 版本:2.15.6

我使用 ProducerTemplate 发送 http 请求并获得如下响应。

from("direct:getContact")
.process(new Processor() {
                    @Override
                    public void process(Exchange exchange) throws Exception {
                        CamelContext context = exchange.getContext();
                        ProducerTemplate producerTemplate = context.createProducerTemplate();
Contact contact = producerTemplate.requestBodyAndHeaders( 
                                "http://localhost:8080/api/contact/2345", 
                                null, headers, Contact.class); 

logger.info("Contact is: " + new ObjectMapper().writeValueAsString(contact)); 

exchange.getOut().setBody(contact);

});

我得到的联系人为空。

当我尝试将其作为对象获取时，如下所示:

Object contact = producerTemplate.requestBodyAndHeaders( 
                                "http://localhost:8080/api/contact/2345", 
                                null, headers); 


logger.info("Contact is: " + new ObjectMapper().writeValueAsString(contact)); 

com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.apache.camel.converter.stream.CachedOutputStream$WrappedInputStream and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEA

NS))

为什么 ProducerTemplate 无法解码对指定对象的响应？如何才能实现这一目标？

编辑

我观察到的修复如下:如果我首先将输出作为字符串获取，然后将其反序列化，那么它就可以工作。

String responseString = producerTemplate.requestBodyAndHeaders( 
                                    "http://localhost:8080/api/contact/2345", 
                                    null, headers, String.class); 

Contact contact = new ObjectMapper().readValue(responseString, Contact.class);

Answer 1

尝试像这样创建您的路线:

//org.apache.camel.component.jackson.JacksonDataFormat

JacksonDataFormat jacksonDataFormat = new JacksonDataFormat();
jacksonDataFormat.setUnmarshalType(Contact.class);

from("direct:getContact")
    .to("http://localhost:8080/api/contact/2345")
    .unmarshal(jacksonDataFormat);

解码后，正文中应该有 Contant 对象。

依赖项来自:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-jackson</artifactId>
    <version>2.15.6</version>
</dependency>