java - 使用 spring-hateoas 使用基于 HAL 的 REST 服务

Question

我正在尝试使用 RestTemplate 类使用基于 HAL 的 REST 服务。响应正文如下所示:

{
  "_embedded": {
    "school:teachers": [
      {
        "name": "Adams",
        "state": "CA",
        "_links": {
          "self": {
            "href": "http://localhost:8080/api/teachers/1"
          }
        }
      },
      {
        "name": "Barnes",
        "state": "FL",
        "_links": {
          "self": {
            "href": "http://localhost:8080/api/teachers/2"
          }
        }
      },
      {
        "name": "Armstrong",
        "state": "GA",
        "_links": {
          "self": {
            "href": "http://localhost:8080/api/teachers/3"
          }
        }
      }
    ]
  },
  "_links": {
    "curies": [
      {
        "href": "http://localhost:8080/docs/html5/{rel}.html",
        "name": "school",
        "templated": true
      }
    ]
  }
}

Teacher类看起来像这样:

public class Teacher {
    private String name;
    private String state;

    // getters and setters...
}

GET 方法的 REST 服务的返回类型是 ResponseEntity<Resources<Resource<Component>>> .因此，我在客户端代码中的请求如下所示:

...
RestTemplate restTemplate = new RestTemplate();

Map<String, Object> dummy = new HashMap<>();
HttpEntity<String> httpEntity = getHttpEntity(); 

ResponseEntity<Resources<Resource<Teacher>>> response = restTemplate.exchange(url,
                HttpMethod.GET,
                httpEntity,
                new ParameterizedTypeReference<Resources<Resource<Teacher>>>() {});

Resources<Resource<Teacher>> resources = response.getBody();
...

当我使用响应类型发出请求时 ParameterizedTypeReference响应内容为空。当我用 String 做的时候我检索内容列表。

我应该如何请求以响应类型 ParameterizedTypeReference 检索它将其直接映射到 POJO 中？

Answer 1

当然，你应该选择 Traverson

Traverson client = new Traverson(new URI("http://localhost:8080/api/"), 
         MediaTypes.HAL_JSON);
    Resources<Resource<Teacher>> teachers = client
        .follow("school:teachers")
        .toObject(new ResourcesType<Resource<Teacher>>(){});

https://docs.spring.io/spring-hateoas/docs/current/reference/html/#client.traverson