RestTemplate安卓：RestClientException：无法提取响应：未找到合适的HttpMessageConverter

Question

我正在使用Android resttemplate和MappingJacksonHttpMessageConverter。对于一些url，交换运作良好，但某些url会引发异常。Resttemplate实例化。

restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(new MappingJacksonHttpMessageConverter());
restTemplate.getMessageConverters().add(new StringHttpMessageConverter());
rootUrl = "http://someserver.com"

交换功能：

public Questions loadQuestQuestions(int quest_id, String token) {
    HashMap<String, Object> urlVariables = new HashMap<String, Object>();
    urlVariables.put("quest_id", quest_id);
    urlVariables.put("token", token);
    HttpHeaders httpHeaders = new HttpHeaders();
    httpHeaders.setAccept(Collections.singletonList(MediaType.parseMediaType("application/json")));
    HttpEntity<Object> requestEntity = new HttpEntity<Object>(httpHeaders);
    return restTemplate.exchange(rootUrl.concat("/tasks/{quest_id}/questions?token={token}"), HttpMethod.GET, requestEntity, Questions.class, urlVariables).getBody();
}

问题 -

import org.codehaus.jackson.map.annotate.JsonRootName;
import java.util.LinkedList;

/**
 * Wrapper for collection
*/
@JsonRootName(value = "questions")
public class Questions extends LinkedList<Question> {
}

问题包含所有必要的注释，包括@JsonRootName

收到的Json内容类型为'application/json'，一切都正确，并且最近运行良好。但是抛出了异常：org.springframework.web.client.RestClientException: Could not extract response: no suitable HttpMessageConverter found for response type [Questions] and content type [application/json;charset=utf-8]

- Vlad Bogomolov

Answer 1

我看不出你的代码有什么问题。Spring 3.2.x 添加了使用Jackson 2的转换器-MappingJackson2HttpMessageConverter。也许你可以尝试使用这个转换器。这解决了我过去遇到的类似问题。确保你的POJOs有Jackson 2注释。希望这能帮到你。

RestTemplate template = new RestTemplate();
List<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>();
MappingJackson2HttpMessageConverter map = new MappingJackson2HttpMessageConverter();
messageConverters.add(map);
template.setMessageConverters(messageConverters);
MyClass msg = template.postForObject(url, request, MyClass.class);

- nilesh