如何将 json 对象从我的 android 应用程序发送到服务器

Question

I'm at a bit of a loss as to how to send a json object from my android application to the database

As I am new to this I'm not too sure where I've gone wrong, I've pulled the data from the XML and I have no clue how to then post the object to our server.

any advice would be really appreciated

 package mmu.tom.linkedviewproject;
    
    import android.content.Intent;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.util.Log;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.ImageButton;
    
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpResponse;
    import org.apache.http.client.ClientProtocolException;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.impl.client.DefaultHttpClient;
    import org.apache.http.util.EntityUtils;
    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;
    
    import java.io.IOException;
    
    /**
     * Created by Tom on 12/02/2016.
     */
    public class DeviceDetailsActivity extends AppCompatActivity {

    private EditText address;
    private EditText name;
    private EditText manufacturer;
    private EditText location;
    private EditText type;
    private EditText deviceID;


    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_device_details);

        ImageButton button1 = (ImageButton) findViewById(R.id.image_button_back);
        button1.setOnClickListener(new View.OnClickListener() {
            Class ourClass;

            public void onClick(View v) {

                Intent intent = new Intent(DeviceDetailsActivity.this, MainActivity.class);
                startActivity(intent);
            }
        });


        Button submitButton = (Button) findViewById(R.id.submit_button);

        submitButton.setOnClickListener(new View.OnClickListener() {
            Class ourClass;

            public void onClick(View v) {

                sendDeviceDetails();
            }
        });

        setContentView(R.layout.activity_device_details);

        this.address = (EditText) this.findViewById(R.id.edit_address);
        this.name = (EditText) this.findViewById(R.id.edit_name);
        this.manufacturer = (EditText) this.findViewById(R.id.edit_manufacturer);
        this.location = (EditText) this.findViewById(R.id.edit_location);
        this.type = (EditText) this.findViewById(R.id.edit_type);
        this.deviceID = (EditText) this.findViewById(R.id.edit_device_id);

    }




        protected void onPostExecute(JSONArray jsonArray) {

            try
            {
                JSONObject device = jsonArray.getJSONObject(0);

                name.setText(device.getString("name"));
                address.setText(device.getString("address"));
                location.setText(device.getString("location"));
                manufacturer.setText(device.getString("manufacturer"));
                type.setText(device.getString("type"));
            }
            catch(Exception e){
                e.printStackTrace();
            }




        }

    public JSONArray sendDeviceDetails() {
        // URL for getting all customers


        String url = "http://IP-ADDRESS:8080/IOTProjectServer/registerDevice?";

        // Get HttpResponse Object from url.
        // Get HttpEntity from Http Response Object

        HttpEntity httpEntity = null;

        try {

            DefaultHttpClient httpClient = new DefaultHttpClient();  // Default HttpClient
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);

            httpEntity = httpResponse.getEntity();


        } catch (ClientProtocolException e) {

            // Signals error in http protocol
            e.printStackTrace();

            //Log Errors Here


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


        // Convert HttpEntity into JSON Array
        JSONArray jsonArray = null;
        if (httpEntity != null) {
            try {
                String entityResponse = EntityUtils.toString(httpEntity);
                Log.e("Entity Response  : ", entityResponse);

                jsonArray = new JSONArray(entityResponse);

            } catch (JSONException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return jsonArray;


    }


}


   

Answer 1

You need to be using an AsyncTask class to communicate with your server. Something like this:

This is in your onCreate method.

Button submitButton = (Button) findViewById(R.id.submit_button);

submitButton.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        JSONObject postData = new JSONObject();
        try {
            postData.put("name", name.getText().toString());
            postData.put("address", address.getText().toString());
            postData.put("manufacturer", manufacturer.getText().toString());
            postData.put("location", location.getText().toString());
            postData.put("type", type.getText().toString());
            postData.put("deviceID", deviceID.getText().toString());

            new SendDeviceDetails().execute("http://52.88.194.67:8080/IOTProjectServer/registerDevice", postData.toString());
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
});

This is a new class within you activity class.

private class SendDeviceDetails extends AsyncTask<String, Void, String> {

    @Override
    protected String doInBackground(String... params) {

        String data = "";

        HttpURLConnection httpURLConnection = null;
        try {

            httpURLConnection = (HttpURLConnection) new URL(params[0]).openConnection();
            httpURLConnection.setRequestMethod("POST");

            httpURLConnection.setDoOutput(true);

            DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
            wr.writeBytes("PostData=" + params[1]);
            wr.flush();
            wr.close();

            InputStream in = httpURLConnection.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(in);

            int inputStreamData = inputStreamReader.read();
            while (inputStreamData != -1) {
                char current = (char) inputStreamData;
                inputStreamData = inputStreamReader.read();
                data += current;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (httpURLConnection != null) {
                httpURLConnection.disconnect();
            }
        }

        return data;
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        Log.e("TAG", result); // this is expecting a response code to be sent from your server upon receiving the POST data
    }
}

The line: httpURLConnection.setRequestMethod("POST"); makes this an HTTP POST request and should be handled as a POST request on your server.

Then on your server you will need to create a new JSON object from the "PostData" which has been sent in the HTTP POST request. If you let us know what language you are using on your server then we can write up some code for you.

Answer 2

As per your current code implementation you have onPostExecute method but there is no onPreExecute and doInBackgound method. Starting from Android 3.0 all network operations need to be done on the background thread. So you need to use Asynctask that will perform the actual sending of the request in the background and in the onPostExecute handle the result returned by the doInbackground method.

Here is what you need to do.

1. Create a Asynctask class and override all the necessary methods.
2. The sendDeviceDetails method will eventually go inside the doInBackgound method.
3. onPostExecute will handle the result returned.

As far as sending a JSON object is concerned, you can do it as follows,

Code snippet borrowed from here

 protected void sendJson(final String email, final String pwd) {
    Thread t = new Thread() {

        public void run() {
            Looper.prepare(); //For Preparing Message Pool for the child Thread
            HttpClient client = new DefaultHttpClient();
            HttpConnectionParams.setConnectionTimeout(client.getParams(), 10000); //Timeout Limit
            HttpResponse response;
            JSONObject json = new JSONObject();

            try {
                HttpPost post = new HttpPost(URL);
                json.put("email", email);
                json.put("password", pwd);
                StringEntity se = new StringEntity( json.toString());  
                se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
                post.setEntity(se);
                response = client.execute(post);

                /*Checking response */
                if(response!=null){
                    InputStream in = response.getEntity().getContent(); //Get the data in the entity
                }

            } catch(Exception e) {
                e.printStackTrace();
                createDialog("Error", "Cannot Estabilish Connection");
            }

            Looper.loop(); //Loop in the message queue
        }
    };

    t.start();      
}

This is just one of the ways. You can go for an Asynctask implementation as well.

Answer 3

You should use web service to send data from your app to your server because it will make your work easy and smooth. For that you have to create web service in any server side language like php,.net or even you can use jsp(java server page).

You have to pass all items from your Edittexts to web service.Work of adding data to server will be handled by web service

Answer 4

Button submitButton = (Button) findViewById(R.id.submit_button);

submitButton.setOnClickListener(new View.OnClickListener() {

    public void onClick(View v) {

        JSONObject postData = new JSONObject();

        try {
            postData.put("name", name.getText().toString());
            postData.put("address", address.getText().toString());
            postData.put("manufacturer", manufacturer.getText().toString());
            postData.put("location", location.getText().toString());
            postData.put("type", type.getText().toString());
            postData.put("deviceID", deviceID.getText().toString());
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
});