如何在Android和ASP.net MVC之间发送和接收JSON

Question

如何在Android和ASP.Net MVC中发送和接收JSON数据？ 我有一个Android Login应用程序，它具有Login活动类和JSONParser类。 使用JSONParser类，我将mvc位置的URL，“ POST”参数和我的参数用户名，密码（作为json）传递给MVC。 我有一个接受用户名和密码的ASP.net mvc代码，如果找到匹配项，它将以“用户名”：“ admin”，“成功”：1返回json数据。

Login Activity类的代码是：

protected String doInBackground(String... arg0) {
    // TODO Auto-generated method stub

    new Thread() {          
        // Running Thread.
        public void run() {
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("userid", username.getText().toString().trim()));
            params.add(new BasicNameValuePair("password", password.getText().toString().trim()));

            JSONObject json = jsonParser.makeHttpRequest("http://localhost:8012/Login/Login","GET", params);
            Log.d("Create Response", json.toString());
            try {
                    int success = json.getInt("success");
                    if (success == 1) {

                        Intent newregistrationIntent = new Intent(MainActivity.this,mydashActivity.class);
                        startActivityForResult(newregistrationIntent, 0);
                    } 
                    else 
                    {
                                i=1;
                                flag=1;
                    }
                } catch (JSONException e) {
                            e.printStackTrace();
                }
        }
    }.start();


    return null;




}

JSONParser的代码是：

    public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    // constructor
    public JSONParser() {

    }

    // function get json from url
    // by making HTTP POST or GET mehtod
    public JSONObject makeHttpRequest(String url, String method,
            List<NameValuePair> params) {

        // Making HTTP request
        try {

            // check for request method
            if(method == "POST"){
                // request method is POST
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));


                httpPost.setHeader("Content-type", "application/json");





                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            }else if(method == "GET"){
                // request method is GET
                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }           


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

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

我的ASP.Net MVC代码是：

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using MvcApplication1.Models;
using System.Web.Script.Serialization;

namespace MvcApplication1.Controllers
{
    public class LoginController : Controller
    {
        Dictionary<string, object> loginParam = new Dictionary<string, object>();
        //
        // GET: /Login/

        [HttpGet]
        public ActionResult Login()
        {
            return View();
        }
        [HttpPost]
        public ActionResult Login(Login cs)
        {
            return Json(new { username="admin", success = 1 });

        }

        [HttpGet]
        public ActionResult Profile()
        {
            return View();
        }
        [HttpPost]
        public ActionResult Profile(Login cs)
        {
            return View("");
        }


    }
}

我不确定实际上是否从android到mvc代码建立了连接。 我也不确定Android代码是否在Login（）上击中了MVC控制器。 如何确保JSON数据是从Android发送的，以及数据是从MVC代码返回的？

注意：我实际上不是在比较MVC代码中的数据。 我只是返回数据。 这是我的第一个MVC代码。

Answer 1

 public static String POST( String username,String password){
    String url=Constants.url_registration;
    InputStream inputStream = null;
    String result = "";
    try {
        // 1. create HttpClient
        HttpClient httpclient = new DefaultHttpClient();
        // 2. make POST request to the given URL
        HttpPost httpPost = new HttpPost(url);
        String json = "";

        // 3. build jsonObject
        JSONObject jsonObject = new JSONObject();
        jsonObject.accumulate("username", username);
        jsonObject.accumulate("password", password);


        // 4. convert JSONObject to JSON to String
        json = jsonObject.toString();

        // ** Alternative way to convert Person object to JSON string usin Jackson Lib 
        // ObjectMapper mapper = new ObjectMapper();
        // json = mapper.writeValueAsString(person); 

        // 5. set json to StringEntity
        StringEntity se = new StringEntity(json);

        // 6. set httpPost Entity
        httpPost.setEntity(se);

        // 7. Set some headers to inform server about the type of the content   
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-type", "application/json");
        // 8. Execute POST request to the given URL
        HttpResponse httpResponse = httpclient.execute(httpPost);
        // 9. receive response as inputStream
        inputStream = httpResponse.getEntity().getContent();
        // 10. convert inputstream to string
        if(inputStream != null)
            result = convertInputStreamToString(inputStream);
        else
            result = "Did not work!";

    } catch (Exception e) {
        Log.d("InputStream", e.getLocalizedMessage());
    }

    // 11. return result
    return result;
}

Answer 2

因为您使用了“获取”方法：

JSONObject json = jsonParser.makeHttpRequest("http://localhost:8012/Login/Login","GET", params);

登录方法为[httpPost]

[HttpPost] public ActionResult Login(Login cs) { return Json(new { username="admin", success = 1 });

}