JsonClient.java

package com.soygul.jsonclient;

import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * HTTP client with JSON content type by default.
 */
public class JsonClient {
    private final Gson gson = new Gson();

    public <T> T get(String uri, Class<T> dataType) {
        try {
            URL url = new URL(uri);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setRequestProperty("Accept", "application/json");
            connection.connect();
            int status = connection.getResponseCode();

            switch (status) {
                case 200:
                case 201:
                    /*Bitmap bitmap = BitmapFactory.decodeStream(connection.getInputStream());
                    ImageView imageView = (ImageView) findViewById(R.id.image_view);
                    imageView.setImageBitmap(bitmap);*/
                    BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                    StringBuilder response = new StringBuilder();
                    String line;
                    while ((line = reader.readLine()) != null) {
                        response.append(line);
                    }
                    reader.close();
                    return gson.fromJson(response.toString(), dataType);
            }

        } catch (MalformedURLException ex) {
            //Logger.getLogger(DebugServer.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            //Logger.getLogger(DebugServer.class.getName()).log(Level.SEVERE, null, ex);
        }
        return null;
    }

    public <T> T post(String uri, Object data, Class<T> dataType) {
        try {
            URL url = new URL(uri);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "application/json");
            connection.setRequestProperty("Accept", "application/json");
            connection.setDoOutput(true);
            String postData = new Gson().toJson(data);
            connection.connect();
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream()));
            writer.write(postData);
            writer.flush();
            writer.close();
            int status = connection.getResponseCode();

            switch (status) {
                case 200:
                case 201:
                    BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                    StringBuilder response = new StringBuilder();
                    String line;
                    while ((line = reader.readLine()) != null) {
                        response.append(line);
                    }
                    reader.close();
                    Gson gson = new Gson();
                    return gson.fromJson(response.toString(), dataType);
            }

        } catch (MalformedURLException ex) {
            //Logger.getLogger(DebugServer.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            //Logger.getLogger(DebugServer.class.getName()).log(Level.SEVERE, null, ex);
        }
        return null;
    }
}