PagedResources<Resource 和 RestTemplate 不起作用 [英] PagedResources<Resource and RestTemplate does not works

问题描述

我正在使用 Spring Boot REST 示例.在此，我使用 RestTemplate 调用返回 PagedResources> 对象的端点.但是通过RestTemplate调用时，却没有得到任何内容.然而，该服务构建在另一个微服务中，该服务可通过 Web 轻松访问并可通过 Postman 调用.

I am using Spring Boot REST example. In this I am using RestTemplate to call the endpoint which returns PagedResources<Resource<EmployeeDto>> Object. But when calling through RestTemplate, I did not get any contents. However this service is build in another microservice which easily accessible over web and can be call through Postman.

@GetMapping("/{employeeId}/employees")
public PagedResources<Resource<EmployeeDto>> getEmployyes(@PathVariable(name="employeeId") String employeeId, 
        @RequestParam(defaultValue="0",required = false, name="page") Integer page, 
        @RequestParam(defaultValue="25",required = false, name = "size") Integer size,
        @RequestParam(defaultValue="billingNumber") String sortParam,
        @RequestParam(defaultValue="ASC",required = false) Direction direction,
        Pageable pageable, HttpServletRequest request) throws IOException{

    return employeeService.getEmployeesByCid(employeeId, request);
}

我使用了下面的代码，但它没有给我任何内容.

I used below code and it gives me no contents.

String uri = "http://localhost:8080/employee-api/employees/160166/employees?page=0&size=25";

RestTemplate template = new RestTemplate();
ResponseEntity<PagedResources<Resource<EmployeeDto>>> studentResponse = template
        .exchange(uri, HttpMethod.GET, null, new TypeReferences.PagedResourcesType<Resource<EmployeeDto>>(){});
System.out.println(studentResponse.getBody());

如果我在下面使用，那么我会得到响应.

If I used below, then I get the response.

final ResponseEntity<String> studentResponse = template
                .exchange(URL, HttpMethod.GET, null, String.class);

注意:如果我通过 Postman 执行代码，我会得到以下响应.

Note: If I execute code through Postman I get below response.

{
  "_embedded": {
    "employeeDto": [
      {
        "employeeNumber": "3109194",
        "status": "A"
      },
      {
        "employeeNumber": "3109224",
        "status": "A"
      },
      {
        "employeeNumber": "3109514",
        "status": "A"
      },
      {
        "employeeNumber": "3109519",
        "status": "A"
      }
    ]
  },
  "_links": {
    "first": {
      "href": "http://localhost:8080/customers/1/employee-numbers?sortParam=employeeNumber&page=0&size=4&sort=employeeNumber,asc"
    },
    "prev": {
      "href": "http://localhost:8080/customers/1/employee-numbers?sortParam=employeeNumber&page=0&size=4&sort=employeeNumber,asc"
    },
    "self": {
      "href": "http://localhost:8080/customers/1/employee-numbers?sortParam=employeeNumber&page=1&size=4&sort=employeeNumber,asc"
    },
    "next": {
      "href": "http://localhost:8080/customers/1/employee-numbers?sortParam=employeeNumber&page=2&size=4&sort=employeeNumber,asc"
    },
    "last": {
      "href": "http://localhost:8080/customers/1/employee-numbers?sortParam=employeeNumber&page=3&size=4&sort=employeeNumber,asc"
    }
  },
  "page": {
    "size": 4,
    "totalElements": 14,
    "totalPages": 4,
    "number": 1
  }
}

推荐答案

我能够通过查看 http://izeye.blogspot.com/2015/01/consume-spring-data-rest-hateoas-hal.html 和 为什么 RestTemplate 不将响应表示绑定到 PagedResources?.

I was able to solved this by looking at http://izeye.blogspot.com/2015/01/consume-spring-data-rest-hateoas-hal.html and Why does RestTemplate not bind response representation to PagedResources?.

然而，这是我开发的代码，效果很好.

However, this is the code I developed which works very fine.

public class Demo {
    private static RestTemplate restTemplate() {
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        mapper.registerModule(new Jackson2HalModule());

        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        converter.setSupportedMediaTypes(MediaType.parseMediaTypes("application/hal+json"));
        converter.setObjectMapper(mapper);

        return new RestTemplate(Collections.<HttpMessageConverter<?>> singletonList(converter));
    }

    public static void main(String[] args) throws JsonParseException, JsonMappingException, IOException {
        String URL = "http://localhost:8080/employee-api/employees/160166/employees?page=0&size=25";

        RestTemplate restTemplate = restTemplate();

        ResponseEntity<PagedResources<Resource<EmployeeDto>>> result = restTemplate.exchange(URL, HttpMethod.GET,
                null/* httpEntity */, new ParameterizedTypeReference<PagedResources<Resource<EmployeeDto>>>() {});
        PagedResources<Resource<EmployeeDto>> body = result.getBody();
        ObjectMapper mapper = new ObjectMapper();
        String writeValueAsString = mapper.writeValueAsString(body);

        System.out.println(mapper.writeValueAsString(body));
    }
}

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