使用Java对距离矩阵Api的响应

Question

我正在尝试使用Google距离矩阵API创建一个显示2点之间距离的代码。但是，当我尝试通过Postman运行它时，出现错误：Unexpected '<'。我不知道如何显示如下响应：

{
   "destination_addresses" : [ "San Francisco, Californie, États-Unis" ],
   "origin_addresses" : [ "Seattle, Washington, États-Unis" ],
   "rows" : [
      {
         "elements" : [
            {
               "distance" : {
                  "text" : "1 300 km",
                  "value" : 1299878
               },
               "duration" : {
                  "text" : "12 heures 32 minutes",
                  "value" : 45146
               },
               "status" : "OK"
            }
         ]
      }
   ],
   "status" : "OK"
}

提供了DistanceController：

@RestController
@CrossOrigin(value = "*")
@RequestMapping(value = "/distance")
public class DistanceController {

    private final DistanceService distanceService;

    @Autowired
    public DistanceController(DistanceService distanceService) {
        this.distanceService = distanceService;
    }


   @RequestMapping(value = "/distance", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<String> calculate(
            @RequestBody DistanceCalculationDTO request) throws IOException {
        String response = distanceService.distanceCalculation(request);
       try{
          return new ResponseEntity<>(response, HttpStatus.OK);
       } catch (Exception e){
           return new ResponseEntity<>(response, HttpStatus.OK);
       }

    }
}

提供了DistanceServiceImpl：

@Service
public class DistanceServiceImpl implements DistanceService {

    @Autowired
    DistanceService distanceService;    

    private static final String API_KEY = "";
    OkHttpClient client = new OkHttpClient();

@Override
    public String distanceCalculation(Distance request)
        throws IOException {

        String url = "https://maps.googleapis.com/map/api/distancematrix/json?origins=" +
        request.getOrigin() + "&destination" + request.getDestination() + API_KEY;
        Request request2 = new Request.Builder()
            .url(url)
            .build();

        Response response = client.newCall(request2).execute();
        return response.body().string();
    }
}

您能否至少分享一个有关如何实现我期望的JSON响应的示例？