import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;


/**
 * Real-time Shipment Tracking
 *
 * @author https://www.kd100.com/
 *
 */
public class RealTimeTracking {

    private static final String URL = "https://www.kd100.com/api/v1/tracking/realtime";
    //You can find your ApiKey on https://app.kd100.com/api-managment
    private static final String API_KEY = "";
    //You can find your Secret on https://app.kd100.com/api-managment
    private static final String SECRET = "";
    private static final int CONNECT_TIMEOUT = 1000;
    private static final int READ_TIMEOUT = 5000;

    public static void main(String[] args) {
        String carrier_id = "dhl";
        String tracking_number = "9926933413";
        String phone = "95279527";
        String ship_from = "Toronto, Canada";
        String ship_to = "Los Angeles, CA, United States";

        RealTimeTracking demo = new RealTimeTracking();
        String result = demo.getData(carrier_id, tracking_number, phone, ship_from, ship_to);
        System.out.println(result);
    }



    public String getData(String carrier_id, String tracking_number, String phone, String ship_from, String ship_to) {

        String param = "{" +
                "\"carrier_id\": \""+carrier_id+"\"," +
                "\"tracking_number\": \""+tracking_number+"\"," +
                "\"phone\": \""+phone+"\"," +
                "\"ship_from\": \""+ship_from+"\"," +
                "\"ship_to\": \""+ship_to+"\"," +
                "\"area_show\": 1," +
                "\"order\": \"desc\"" +
                "}";

        String signature = MD5Utils.encode(param + API_KEY + SECRET);
        return this.post(param,signature);
    }


    public String post(String param,String signature) {
        StringBuffer response = new StringBuffer("");

        byte[] data = param.getBytes();

        BufferedReader reader = null;
        OutputStream out = null;
        try {

            URL url = new URL(URL);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setConnectTimeout(CONNECT_TIMEOUT);
            conn.setReadTimeout(READ_TIMEOUT);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setRequestProperty("Content-Length", String.valueOf(data.length));
            conn.setRequestProperty("API-Key",API_KEY);
            conn.setRequestProperty("signature",signature);
            conn.setDoOutput(true);

            out = conn.getOutputStream();
            out.write(data);

            reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));

            String line = "";
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != out){
                    out.flush();
                    out.close();
                }
                if (null != reader) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return response.toString();
    }
}


class MD5Utils {
    private static MessageDigest mdigest = null;
    private static char digits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

    private static MessageDigest getMdInst() {
        if (null == mdigest) {
            try {
                mdigest = MessageDigest.getInstance("MD5");
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            }
        }
        return mdigest;
    }

    public static String encode(String s) {
        if(null == s) {
            return "";
        }

        try {
            byte[] bytes = s.getBytes();
            getMdInst().update(bytes);
            byte[] md = getMdInst().digest();
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = digits[byte0 >>> 4 & 0xf];
                str[k++] = digits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}