使用 ASP.NET Web API 调用 Java Web Service

Question

I have an ASP.NET Web API which is supposed to call a java addition web service. When i run the java web service and type url http://localhost:8080/addition/9/6 i get {"firstNumber":9,"secondNumber":6,"sum":15} as the output data. Right now, i want to use the ASP.NET Web API to call and display that data when i run the ASP.NET Web API application. How do i go about doing that?

Here are my codes:

ASP.NET Web API Codes

RestfulClient.cs

public class RestfulClient     
{
    private string BASE_URL = "http://localhost:8080/addition/";
    public Task<string> addition()
    {
        {
            try
            {
                var client = new HttpClient();
                client.BaseAddress = new Uri(BASE_URL);
                client.DefaultRequestHeaders.Accept.Add(
                    new MediaTypeWithQualityHeaderValue("application/json"));
                HttpResponseMessage response = client.GetAsync("addition").Result;
                return response.Content.ReadAsStringAsync();                 
            }
            catch (Exception e)
            {
                HttpContext.Current.Server.Transfer("ErrorPage.html");
            }
            return null;
        }
    }
}

ApiController.cs

private RestfulClient restfulClient = new RestfulClient();

    public ActionResult Index()
    {

        var Result1 = restfulClient.addition().Result;
        return Content(Result1);
    }

Java Web Service Codes

AdditionController.java

@RestController
public class AdditionController {

private static final String template = " %s";
private static int getSum;

@RequestMapping("/addition/{param1}/{param2}")
@ResponseBody 

public Addition getSum 
            (@PathVariable("param1") int firstNumber,@PathVariable("param2") int secondNumber) {
return new Addition(
        (String.format(template, firstNumber)), String.format(template, secondNumber));
  }
}  

Someone please help me. Thank you so much in advance.

Answer 1

According to the Java service, the URL you are calling from the client is not formatted correctly based on your base URL and the one used in the GetAsync .

public class RestfulClient {
    private static HttpClient client;
    private static string BASE_URL = "http://localhost:8080/";

    static RestfulClient() {
        client = new HttpClient();
        client.BaseAddress = new Uri(BASE_URL);
        client.DefaultRequestHeaders.Accept.Add(
            new MediaTypeWithQualityHeaderValue("application/json"));
    }

    public async Task<string> addition(int a, int b) {
        try {
            var endpoint = string.Format("addition/{0}/{1}", a, b);
            var response = await client.GetAsync(endpoint);
            return await response.Content.ReadAsStringAsync();                 
        } catch (Exception e) {
            HttpContext.Current.Server.Transfer("ErrorPage.html");
        }
        return null;
    }
}

The controller would also need to be updated.

public async Task<ActionResult> Index() {
    int a = 9;
    int b = 6;
    var result = await restfulClient.addition(a, b);
    return Content(result);
}

Note the proper use of the HttpClient as suggested in the comments and as well as the use of async/await.