我有两个问题:

如何使用Spring RestTemplate映射JSON对象列表。 如何映射嵌套的JSON对象。

我试图消费https://bitpay.com/api/rates,从http://spring.io/guides/gs/consuming-rest/遵循教程。


当前回答

更简单的方法: 我会给你们看Authorization heard和unauthorization header:

未经授权: a.进行依赖注入(构造函数注入): 你也可以选择字段注入。我考虑了构造函数注入。

public class RestTemplateService {
private final RestTemplate template;
public RestTemplateService(RestTemplate template) {
    this.template = template;
  }
}

b.调用getList()方法:

public ResponseEntity<List> getResponseList(String url, HttpMethod type) {
    return template.exchange(url, type, new HttpEntity<>(new HttpHeaders()), List.class);
  }

授权:我喜欢小方法。所以我把这些功能分开:

 public ResponseEntity<List> getResponse(String url, HttpMethod type) {
    return template.exchange(url, type, getRequest(getHeaders(USERNAME, PASS)), List.class);
  }

 private HttpEntity<String> getRequest(HttpHeaders headers) {
    return new HttpEntity<>(headers);
  }

 private HttpHeaders getHeaders(String username, String password) {
    HttpHeaders headers = new HttpHeaders();
    headers.add("Authorization", "Basic " + new String(Base64.encodeBase64((username + ":" + password).getBytes())));
    return headers;
  }

希望问题能得到解决!

其他回答

作为一个通用模块,Page<?>对象可以被模块反序列化,就像JodaModule, Log4jJsonModule等。参考我的回答。使用Pageable字段测试端点时出现JsonMappingException

这里提到了3种检索对象列表的方法。所有这些都将完美地工作

@RequestMapping(value = "/emp2", produces = "application/json")
public List<Employee> getEmp2()
{
    HttpHeaders headers = new HttpHeaders();
    headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
    HttpEntity<String> entity = new HttpEntity<String>(headers);
    ResponseEntity<List<Employee>> response = restTemplate.exchange(
            "http://hello-server/rest/employees", HttpMethod.GET,entity, 
    new ParameterizedTypeReference<List<Employee>>() {});
    return response.getBody();
}

(或)

@RequestMapping(value = "/emp3", produces = "application/json")
public List<Employee> getEmp3()
{
    Employee[] empArray = restTemplate.getForObject("http://hello-server/rest/employees", Employee[].class);
    List<Employee> emp= Arrays.asList(empArray);
    return emp;
}

(或)

    @RequestMapping(value = "/emp4", produces = "application/json")
public Employee[] getEmp4()
{
    ResponseEntity<Employee[]> responseEntity = restTemplate.getForEntity("http://hello-server/rest/employees", Employee[].class);
    Employee[] empList = responseEntity.getBody();
    //MediaType contentType = responseEntity.getHeaders().getContentType();
    //HttpStatus statusCode = responseEntity.getStatusCode();
    return  empList;
}

Employee.class

public class Employee {

private Integer id;
private String name;
private String Designation;
private String company;

//getter setters and toString()

}

经过多次测试,这是我发现的最好的方法:)

Set<User> test = httpService.get(url).toResponseSet(User[].class);

这就是你所需要的

public <T> Set<T> toResponseSet(Class<T[]> setType) {
    HttpEntity<?> body = new HttpEntity<>(objectBody, headers);
    ResponseEntity<T[]> response = template.exchange(url, method, body, setType);
    return Sets.newHashSet(response.getBody());
}

我从这个帖子https://jira.spring.io/browse/SPR-8263找到了工作。

基于这篇文章,你可以返回一个类似这样的列表:

ResponseEntity<? extends ArrayList<User>> responseEntity = restTemplate.getForEntity(restEndPointUrl, (Class<? extends ArrayList<User>>)ArrayList.class, userId);

在我的情况下,我更喜欢提取一个字符串,然后使用JsonNode接口浏览上下文

    var response =  restTemplate.exchange("https://my-url", HttpMethod.GET, entity,  String.class);
    if (response.getStatusCode() == HttpStatus.OK) {
        var jsonString = response.getBody();
        ObjectMapper mapper = new ObjectMapper();
        JsonNode actualObj = mapper.readTree(jsonString);           
        
        System.out.println(actualObj);  
    }

或者很快

ObjectNode actualObj= restTemplate.getForObject("https://my-url", ObjectNode.class);

然后读取内部数据与路径表达式,即。

boolean b = actualObj.at("/0/states/0/no_data").asBoolean();