Android将Java中的POST请求发送到ASP.net Web API

Question

When I used HttpUrlConnection to send POST request from Android to ASP.net Web API. It seems not working.

String baseUrl = "http://<IP Address>/Save/Document";
URL url = new URL(baseUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json; charset=utf-8");
DataOutputStream os = new DataOutputStream(conn.getOutputStream());

JSONObject ap = new JSONObject();
// Where data is a JSON string
// Like [{Test: 1}, {Test: 2}]
ap.put("",new Gson().toJson(data));

OutputStreamWriter ap_osw= new OutputStreamWriter(conn.getOutputStream());
ap_osw.write(ap.toString());
ap_osw.flush();
ap_osw.close();

BufferedReader br = new BufferedReader(new InputStreamReader(
                    (conn.getInputStream())));

StringBuilder response = new StringBuilder();
while ((output = br.readLine()) != null) {
    response.append(output);
    response.append('\r');
}
String mes = response.toString();
Log.i("INFO", mes);
conn.disconnect();

When executing the above code, it will have an FileNotFoundException in

conn.getInputStream()

I also tried to implement source code in HttpClient style.

HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(baseUrl);

try {
     StringEntity se = new StringEntity((new Gson()).toJson(data));
     httpPost.setEntity(se);
     httpPost.setHeader("Accept", "application/json");
     httpPost.setHeader("Content-Type", "application/json");

     HttpResponse response = httpClient.execute(httpPost);
     InputStream inputStream = response.getEntity().getContent();

     String result = "";
     if (inputStream != null)
          result = convertInputStreamToString(inputStream);
     else
          result = "Did not work!";

     Log.i("RESPONSE", result);

 } catch (Exception ex) {
     Log.i("Exception", ex.getMessage());
 }
 return output;

And this time, it shows "The requested resource does not support http method 'get'".

I have no ideas how to implement the POST request method to send data from Android to ASP.net Web API. Any recommendations?

Finally, the following coding is my ASP.net Web API for reference.

[HttpPost]
[Route("Save/Document")]
public HttpResponseMessage Post([FromBody]string model)
{
     var resp = new HttpResponseMessage(HttpStatusCode.OK);
     resp.Content = new StringContent(model, System.Text.Encoding.UTF8, "text/plain");
     return resp;
}

Answer 1

Finally, I got a solution to fix this problem. It is due to the POST data in request body can not be read from Web API.

When the request Content-Type is "application/json",

Using string, The request body should be a plain text (eg "Text Message").

[FromBody] string inStr

Using self-defined class, The request body should be a json string (eg { KEY: VALUE })

[FromBody] YourClass inObj

Using array of self-defined class, The request body should be a json array string (eg [{ KEY: VALUE }])

[FromBody] YourClass[] inObj

And the self-defined class should be like as following:-

class YourClass {
    public string KEY { get; set; }
}

Btw. Thanks for all reply and useful information.