从返回ResponseEntity的API获取数据<Object>

Question

我有一个服务通过rest模板调用另一个Api，并且该Api返回ResponseEntity对象。我尝试了一些方法，但无法获取所需的数据。

这是我调用的API的代码

SurveyService.java

     public ResponseEntity<Object> getSurveyData(String searchText) {
        List<SurveyResponse> dataList = new ArrayList<>();
        List<Map<Object, Object>> results =  someRepo.getSurveyData(searchText);
        if(null != results) {
            for (Map<Object, Object> item : results) {
            Survey t = (Survey) ObjectMapper.convertMapToJson(item, Survey.class); //Utility class
                    SurveyResponse response = SurveyResponse.builder()
                        .id(t.getId())
                        .type(t.getType())
                        .name(t.getName())
                        .jobDesc(t.getJobDesc())
                        .build();
        
           
              dataList.add(response);
            }
        }

        return ResponseHandler.generateResponse(SUCCESS, HttpStatus.OK, dataList);

    } 

下面是实用程序响应处理程序类

ResponseHandler.java

  public static ResponseEntity<Object> generateResponse(String message, HttpStatus status, Object responseObj) {
        Map<String, Object> map = new LinkedHashMap<String, Object>();
        map.put(STATUS, status.value());
        map.put(MESSAGE, message);
        map.put(DATA, responseObj);
        return new ResponseEntity<>(map, status);

    }

这是实体类

Survey.java

    @Data
    @Entity
    @AllArgsConstructor
    @NoArgsConstructor
    public class Survey {
    @Id
    private String id;
    private String type;
    private String name;
    private String jobDesc;
    }

Api 的响应如下所示

{
    "status": 200,
    "message": "SUCCESS",
    "data": [
        {
            "id": "12345",
            "type": "person",
            "name": "P1",
            "jobDesc":"QA"
           
        }
    ]
}

这是我的 Service 类中的代码，我创建了一个名为 Survey.java 的实体类来映射来自 Api 的响应

PersonSurveyService.java

public void getSurvey(String personId){
 try {

            ResponseEntity<Map<String, Object>> response = restTemplate.exchange(url+personId, HttpMethod.GET, null,
                    new ParameterizedTypeReference<Map<String, Object>>() {
                    });
            List<Survey> alist = (List<Survey>) response.getBody().get("data");
            System.out.println("checking first element"+alist.get(0).getId());
}
 catch(Exception ex) {
            System.out.println("Exception is:"+ex);
        }

上面的 sysout 打印得很好，直到我打印 alist.get(0) 但当我添加 getId() 时它会抛出以下异常。

Exception is:java.lang.ClassCastException: class java.util.LinkedHashMap cannot be cast to class com.test.entity.Survey (java.util.LinkedHashMap is in module java.base of loader 'bootstrap'; com.test.entity.Survey is in unnamed module of loader 'app')

我尝试了一些其他方法

Approach 1:
ResponseEntity<Survey> response = restTemplate.getForEntity(url + personId, Survey.class);

I do not get any error here but all the fields in Survey object gets mapped as null.

Approach 2:
 
 ResponseEntity<Map<String, Object>> response = restTemplate.exchange(url+personId, HttpMethod.GET, null,
                    new ParameterizedTypeReference<Map<String, Object>>() {
                    });

objectMapper.convertValue(response.getBody(),Survey.class);

Here I get an error: Exception is:java.lang.IllegalArgumentException: Unrecognized field "status"

有关如何从下面的响应对象中正确获取详细信息（id、名称等）的任何输入。

{
    "status": 200,
    "message": "SUCCESS",
    "data": [
        {
            "id": "12345",
            "type": "person",
            "name": "P1",
            "jobDesc":"QA"
           
        }
    ]
}

Answer 1

使用 ResponseEntity 作为 API 的返回类型，并在使用 restemplate 调用它时使用 ObjectNode.class 作为返回类类型。

您可以在生成响应方法中使用它：

ObjectNode nodes = new ObjectMapper().createObjectNode();

nodes.put(STATUS, status.value());
nodes.put(MESSAGE, message);
nodes.put(DATA, responseObj);
return ResponseEntity.status(HttpStatus.OK).body(nodes);

使用剩余模板调用它时，您可以使用如下所示的内容：

ResponseEntity<Map<String, Object>> response = restTemplate.exchange(url+personId, HttpMethod.GET, null, ObjectNode.class);

请尝试一下，让我知道它是否有帮助，否则我们将改变一些事情。