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

/**
 * @Description HmacSHA256算法
 * @Author lvshuy
 * @Version V1.0.0
 * @Date 2021/1/18
 */
public class HmacSHA256Util {

    /**
     * HmacSHA256算法,返回的结果始终是32位
     * @param key 加密的键，可以是任何数据
     * @param content 待加密的内容
     * @return 加密后的内容
     * @throws Exception
     */
    public static byte[] hmacSHA256(byte[] key,byte[] content) throws Exception {
        Mac hmacSha256 = Mac.getInstance("HmacSHA256");
        hmacSha256.init(new SecretKeySpec(key, 0, key.length, "HmacSHA256"));
        byte[] hmacSha256Bytes = hmacSha256.doFinal(content);
        return hmacSha256Bytes;
    }

    /**
     * 将加密后的字节数组转换成字符串
     *
     * @param b 字节数组
     * @return 字符串
     */
    public  static String byteArrayToHexString(byte[] b) {
        StringBuilder hs = new StringBuilder();
        String stmp;
        for (int n = 0; b!=null && n < b.length; n++) {
            stmp = Integer.toHexString(b[n] & 0XFF);
            if (stmp.length() == 1)
                hs.append('0');
            hs.append(stmp);
        }
        return hs.toString().toLowerCase();
    }
    /**
     * sha256_HMAC加密
     * @param message 消息
     * @param secret  秘钥
     * @return 加密后字符串
     */
    public static String hmacSHA256(String secret, String message) throws Exception {
        String hash = "";
        Mac hmacSha256 = Mac.getInstance("HmacSHA256");
        SecretKeySpec secret_key = new SecretKeySpec(secret.getBytes(), "HmacSHA256");
        hmacSha256.init(secret_key);
        byte[] bytes = hmacSha256.doFinal(message.getBytes());
        hash = byteArrayToHexString(bytes);
        return hash;
    }

    public static void main(String[] args) {
        String appSecret = "b06c75b58d1701ff470119a4114f8b45";
        String appId = "10000001";
        String timestamp = "1529853639000";

//        HMAC-SHA256(appSecret，appId + timestamp+去除节点间的空格及换行符的请求体)
        String message = appId + timestamp + "<req><orderId>91303183862452</orderId><notifyUrl></notifyUrl><refundTime>2013-03-22 16:25:26</refundTime><refundFee>24.5</refundFee><refundNo>14252414245</refundNo></req>";
        System.out.println("加密前 =========>"+message);
        String str = "";
        try{
            str = HmacSHA256Util.hmacSHA256(appSecret,message);
            System.out.println("加密后 =========>"+str);
        }catch (Exception e){
            System.out.println("Error HmacSHA256 ===========>" + e.getMessage());
        }

    }

}