在Spring Boot控制器中使用GraphQL API

Question

我需要在我的Spring Boot控制器中使用第三方提供的graphQL API，我尝试了here，但得到了400错误。 以下是代码：

@SuppressWarnings("unchecked")
@RequestMapping(value = "/graphQLTest")
public ResponseEntity<?> testGraphQL() throws JsonProcessingException {

    CloseableHttpClient client= null;
    CloseableHttpResponse response= null;

    client= HttpClients.createDefault();
    HttpPost httpPost= new HttpPost("http://172.30.66.149:3000/graphql");

    httpPost.addHeader("Accept","application/json");

    try {
        StringEntity entity= new StringEntity("{\"query\":\"{hello}\"}");

        httpPost.setEntity(entity);
        response= client.execute(httpPost);
        System.out.println("response: "+response);
    }

    catch(UnsupportedEncodingException e){
        e.printStackTrace();
    }
    catch(ClientProtocolException e){
        e.printStackTrace();
    }
    catch(IOException e){
        e.printStackTrace();
    }

    return null;
}

当我尝试在Postman中调用相同的URL时，我得到了响应，下面是屏幕截图：

但是当我在我的控制器中尝试它时，我得到以下错误，任何人都可以帮助我如何使用某人的GraphQL API。

Error: HttpResponseProxy{HTTP/1.1 400 Bad Request [X-Powered-By: Express, Content-Type: application/json; charset=utf-8, Content-Length: 53, ETag: W/"35-1vperDe+r7EpHry/i+J3wg", Date: Tue, 24 Apr 2018 12:32:52 GMT, Connection: keep-alive] ResponseEntityProxy{[Content-Type: application/json; charset=utf-8,Content-Length: 53,Chunked: false]}}

Answer 1

我只是尝试通过jersey api调用我的graphQL API，如下所示，我能够得到回复。

@SuppressWarnings("unchecked")
@RequestMapping(value = "/graphQLTest")
public ResponseEntity<?> testGraphQL() throws JsonProcessingException {

    JSONObject jsonObj = new JSONObject();     
    jsonObj.put("query", "{\n" + 
        "  hello\n" + 
        "}");

    Client client = Client.create();
    String URL = "http://172.30.66.149:3000";
    WebResource webResource = client.resource(URL);

    ClientResponse response = webResource.type("application/json").accept("application/json").post(ClientResponse.class, jsonObj.toString());
    String output = response.getEntity(String.class);
    System.out.println(output);

    return null;
}

有没有其他方法可以进行此调用，或者特别是graphQL方式？