Java Sample

This Java example is based on the Sprint framework and uses the RestTemplate to make requests.

Signature implemention

import java.util.*;

public class Signature {
    public static String sign(Map<String, Object> params, String apiToken) {
        StringBuilder str = new StringBuilder(apiToken);

        List<String> keys = new ArrayList<>(params.keySet());
        Collections.sort(keys);

        for (String key : keys) {
            Object value = params.get(key);
            if (value != null && !"".equals(value.toString()) && !"sign".equals(key)) {
                str.append("&").append(key).append("=").append(value);
            }
        }

        return md5(str.toString());
    }

    private static String md5(String input) {
        try {
            java.security.MessageDigest md = java.security.MessageDigest.getInstance("MD5");
            byte[] messageDigest = md.digest(input.getBytes());
            StringBuilder hexString = new StringBuilder();
            for (byte b : messageDigest) {
                String h = Integer.toHexString(0xff & b);
                if (h.length() == 1) hexString.append('0');
                hexString.append(h);
            }
            return hexString.toString();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

Create collection order

The following shows how to create a collection order. The payout request is similar.

import org.springframework.http.*;
import org.springframework.web.client.RestTemplate;

import java.util.*;

public class OrderRequest {
    public static void main(String[] args) {
        Map<String, Object> params = new HashMap<>();
        params.put("mch_id", 2050);                         // Merchant ID
        params.put("trans_id", "E1763923463");              // Transaction ID of your system
        params.put("channel", "bank");                      // Channel code
        params.put("amount", "200000.00");                  // Order amount
        params.put("currency", "VND");                      // Currency
        params.put("callback_url", "https://api.blackhole.com"); // Webhook url
        params.put("remarks", "callme");                    // Remarks
        params.put("nonce", UUID.randomUUID().toString().substring(0, 8)); // Random string
        params.put("timestamp", System.currentTimeMillis() / 1000);        // UNIX timestamp

        String apiToken = "0xFAKE_TOKENx0"; // API Token
        params.put("sign", Signature.sign(params, apiToken));

        String gateway = "http://domain/api/v1/mch/pmt-orders";

        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);

        HttpEntity<Map<String, Object>> request = new HttpEntity<>(params, headers);

        try {
            ResponseEntity<Map> response = restTemplate.postForEntity(gateway, request, Map.class);
            if (response.getStatusCode() != HttpStatus.OK) {
                // todo: handle failure
            } else {
                Map<String, Object> body = response.getBody();
                if (body != null && !Objects.equals(body.get("code"), 200)) {
                    String reason = String.valueOf(body.get("message")); // failed reason
                    // todo: handle failure
                } else {
                    // todo: handle success
                }
            }
        } catch (Exception e) {
            // todo: other exception
            e.printStackTrace();
        }
    }
}