Java HmacMD5算法签名

import com.niwodai.csc.service.HmacMD5Sign;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;

import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.util.Map;
import java.util.TreeMap;

/**
 * @ClassName: HmacMD5SignImpl
 * @Description:HmacMD5Sign签名
 * @Author guoh
 * @Date 2018/8/10 17:27
 */
@Service
public class HmacMD5SignImpl implements HmacMD5Sign {

    private Logger logger = LoggerFactory.getLogger(HmacMD5SignImpl.class);

    /**
     * MAC算法可选以下多种算法
     *
     */
    public static final String KEY_MAC = "HmacMD5";

    @Override
    public String getHmacMD5Signature(Map<String, String> requestParam, String key) {
        String data = formPublicParam(requestParam);
        byte[] inputData = data.getBytes();
        SecretKey secretKey = new SecretKeySpec(key.getBytes(), KEY_MAC);
        Mac mac;
        try {
            mac = Mac.getInstance(secretKey.getAlgorithm());
            mac.init(secretKey);
            return byteArrayToHexString(mac.doFinal(inputData));
        } catch (Exception e) {
            logger.error("HmacMD5算法加密失败",e);
        }
        return null;
    }

    /*byte数组转换为HexString*/
    private String byteArrayToHexString(byte[] b) {
        StringBuffer sb = new StringBuffer(b.length * 2);
        for (int i = 0; i < b.length; i++) {
            int v = b[i] & 0xff;
            if (v < 16) {
                sb.append('0');
            }
            sb.append(Integer.toHexString(v));
        }
        return sb.toString();
    }
    /**map参数排序**/
    private String formPublicParam(Map<String, String> requestParam) {
        //所有的参数，这里使用TreeMap， 好处在于天然有序，默认是字母顺序
        Map<String, String> params = new TreeMap<>();
        params.putAll(requestParam);
        //访问的URL
        StringBuffer buffer = new StringBuffer();
        for (Map.Entry<String, String> param : params.entrySet()) {
            buffer.append(param.getKey() + "=" + param.getValue());
        }
        return buffer.toString();
    }

}