以下划线（“ _id”）开头的属性的JSON反序列化无效

Question

Posting the question as I can't find solution specific to below problem.

One of the 3rd part REST service we are consuming return response similar to
{ "_id": "d55eb7c0", "applicationType": "TEST", "applicationId": "uxhJ1hcT1F8bpL3xAWvTjsymNcd1RArv", "description": "Some Description"}

tried to map "_id" attribute as, to follow proper java bean naming

@JsonProperty("_id")
private String id;

which results in following error.

org.springframework.web.client.RestClientException: Could not extract response: no suitable HttpMessageConverter found for response type [class ] and content type [application/json;charset=utf-8]
at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:109)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:917)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:901)

if the field name is private String _id; json response is de-serialised without any issue. but I don't want to name field starting with '_' in our app. We are using Jackson-2.7.3 & Spring RestTemplate to make REST calls.

Implementation for consuming the endpoint. Its a simple GET call using Spring RestTemplate.

HttpEntity<String> requestEntity = new HttpEntity<>(httpHeaders); return restTemplate.exchange(authorizationProperties.getEndpoint() + "/roles", HttpMethod.GET, requestEntity,new ParameterizedTypeReference<Auth0Roles>() {});

Thanks in advance.

Answer 1

I guess you need to apply the annotation on the accessor methods, not the field itself:

   private String id;

   @JsonProperty("_id")
   public String getId() {
      return this.id;
   }
   public void setId(String i) {
      this.id = i;
   }

Answer 2

Its not looking like the problem with JSON. Most probably you are missing the HttpMessageConverter.

Try Adding this dependency

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.8.3</version>
</dependency>