Payment through Vietnam Domestic ATM card

package vn.connectbank.controller;

import java.io.UnsupportedEncodingException;
import java.math.BigDecimal;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.web.client.RestTemplate;

public class CodeExample {

  public static void main(String[] args) {
    CodeExample ex = new CodeExample();
    String paymentUrl = ex.doPayment();
    System.out.println("url thanh toan = "+paymentUrl);
  }
  
  public String doPayment() {
    // url nhan duoc sau khi request thanh cong
    String paymentUrl = "";
    
    /*Thong tin ket noi*/
    String requestUrl = "https://partner.truemoney.com.vn/paymentgw/api/v1/do-payment";
    String accessKey = "";
    String secretKey = "";
    /*end Thong tin ket noi*/
    
    /* Thong tin don hang  */
    // orderId duy nhat ,tu sinh theo thuat toan cua merchant
    String orderId = "";
    // noi dung thong tin don hang kem theo
    String orderInfo = "";
    // merchant dung url nhat ket qua trang thai giao dich.
    String returnUrl = "https://ecom.truemoney.com.vn/";
    // so tien giao dịch
    BigDecimal amount = new BigDecimal(100000);
    //phuong thuc thanh toan . Thanh toan qua vi paymentType=2, qua ngan hang noi dia paymentType=0, qua visa paymentType=1
    String paymentType = "2";
    // ma vi muon thanh toan ,bat buoc neu payment_type=2
    String walletCode = "TRUEMONEY";
    //bank_code co the truyen hoac khong, neu khong truyen se ra man hinh chon bank, neu truyen bank_code se ra trang cua nha cung cap
    String bankCode = "";
    // ngon ngu tieng viet hoac tieng anh (vi or en)
    String language = "vi";
    // chu ki dien tu sinh theo thuat toan HmacSHA256
    String signature = generateSignatures(accessKey, amount, orderId, orderInfo, returnUrl, secretKey);
    /*end thong tin don hang */
    
    PaymentRequest requestPayment = new PaymentRequest();
    requestPayment.setAmount(amount);
    requestPayment.setAccess_key(accessKey);
    requestPayment.setOrder_id(orderId);
    requestPayment.setOrder_info(orderInfo);
    requestPayment.setPayment_type(paymentType);
    requestPayment.setWallet_code(walletCode);
    requestPayment.setBank_code(bankCode);
    requestPayment.setReturn_url(returnUrl);
    requestPayment.setSignature(signature);
    requestPayment.setLanguage(language);
    try {
      PaymentResponse responsePayment = postToHTTPSAddress(requestUrl, requestPayment, PaymentResponse.class);
      if (responsePayment != null) {
        String responseCode = responsePayment.getResponse_code();
        if (responseCode.equals("00")) {
          PaymentBody body = responsePayment.getData();
          if (body != null) {
            paymentUrl = body.getPayment_url();
          }
        }else {
          // merchant handle truong hop request giao dich that bai
        }
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return paymentUrl;
  }
  

  public  T postToHTTPSAddress(String url, K req, Class type) throws Exception {
    RestTemplate restTemplate = new RestTemplate();
    try {
      HttpHeaders headers = new HttpHeaders();
      headers.set("Content-Type", MediaType.APPLICATION_JSON_VALUE);
      headers.add("User-Agent",
          "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36");

      HttpEntity request = new HttpEntity(req, headers);

      T obj = restTemplate.postForObject(url, request, type);
      return obj;
    } catch (Exception e) {
      e.printStackTrace();
    }

    return null;
  }

  public String generateSignatures(String access_key, BigDecimal amount, String orderId, String orderInfo,
      String returnUrl, String secretkey) {

    String requestParam = "access_key=" + access_key + "&amount=" + amount + "&order_id=" + orderId + "&order_info="
        + orderInfo + "&return_url=" + returnUrl;

    return hmacDigest(requestParam, secretkey, "HmacSHA256");
  }

  public static String hmacDigest(String msg, String keyString, String algo) {
    String digest = "";
    try {
      if (keyString != null && keyString.length() > 0) {
        SecretKeySpec key = new SecretKeySpec((keyString).getBytes("UTF-8"), algo);
        Mac mac = Mac.getInstance(algo);
        mac.init(key);
        byte[] bytes = mac.doFinal(msg.getBytes("ASCII"));
        StringBuffer hash = new StringBuffer();
        for (int i = 0; i < bytes.length; i++) {
          String hex = Integer.toHexString(0xFF & bytes[i]);
          if (hex.length() == 1) {
            hash.append('0');
          }
          hash.append(hex);
        }
        digest = hash.toString();
      }
    } catch (UnsupportedEncodingException e) {
      e.printStackTrace();
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (InvalidKeyException e) {
      e.printStackTrace();
    }
    return digest;
  }
  
  
  class PaymentRequest {

    private String access_key;

    private BigDecimal amount;

    private String order_id;

    private String order_info;

    private String return_url;

    private String bank_code;

    private String wallet_code;

    private String payment_type;

    private String language;

    private String signature;

    public String getAccess_key() {
      return access_key;
    }

    public void setAccess_key(String access_key) {
      this.access_key = access_key;
    }

    public BigDecimal getAmount() {
      return amount;
    }

    public void setAmount(BigDecimal amount) {
      this.amount = amount;
    }

    public String getOrder_id() {
      return order_id;
    }

    public void setOrder_id(String order_id) {
      this.order_id = order_id;
    }

    public String getOrder_info() {
      return order_info;
    }

    public void setOrder_info(String order_info) {
      this.order_info = order_info;
    }

    public String getReturn_url() {
      return return_url;
    }

    public void setReturn_url(String return_url) {
      this.return_url = return_url;
    }

    public String getBank_code() {
      return bank_code;
    }

    public void setBank_code(String bank_code) {
      this.bank_code = bank_code;
    }

    public String getWallet_code() {
      return wallet_code;
    }

    public void setWallet_code(String wallet_code) {
      this.wallet_code = wallet_code;
    }

    public String getPayment_type() {
      return payment_type;
    }

    public void setPayment_type(String payment_type) {
      this.payment_type = payment_type;
    }

    public String getLanguage() {
      return language;
    }

    public void setLanguage(String language) {
      this.language = language;
    }

    public String getSignature() {
      return signature;
    }

    public void setSignature(String signature) {
      this.signature = signature;
    }

  }
  
  class PaymentResponse {

    private String response_code;

    private String response_message;

    private PaymentBody data;

    public String getResponse_code() {
      return response_code;
    }

    public void setResponse_code(String response_code) {
      this.response_code = response_code;
    }

    public String getResponse_message() {
      return response_message;
    }

    public void setResponse_message(String response_message) {
      this.response_message = response_message;
    }

    public PaymentBody getData() {
      return data;
    }

    public void setData(PaymentBody data) {
      this.data = data;
    }
  }
  
  class PaymentBody {
    private String payment_url;

    private String trans_ref;

    public String getPayment_url() {
      return payment_url;
    }

    public void setPayment_url(String payment_url) {
      this.payment_url = payment_url;
    }

    public String getTrans_ref() {
      return trans_ref;
    }

    public void setTrans_ref(String trans_ref) {
      this.trans_ref = trans_ref;
    }

  }
  
  
}