Java实现哈希函数/散列算法

// 哈希函数/散列算法
// 根据某个值进行hash值计算，确保唯一性
public class HashUtils {

    private static final String ALGORITHM = "SHA-256";

    public static String sha256Hex(byte[] bytes){
        MessageDigest messageDigest;
        String encodeStr = "";
        try {
            messageDigest = MessageDigest.getInstance(ALGORITHM);
            messageDigest.update(bytes);
            encodeStr = byte2Hex(messageDigest.digest());
        } catch (NoSuchAlgorithmException e) {
            log.error("未知的hash算法{}", ALGORITHM);
        }
        return encodeStr;
    }

    private static String byte2Hex(byte[] bytes){
        StringBuffer stringBuffer = new StringBuffer();
        String temp = null;
        for (int i=0;i<bytes.length;i++){
            temp = Integer.toHexString(bytes[i] & 0xFF);
            if (temp.length()==1){
                //1得到一位的进行补0操作
                stringBuffer.append("0");
            }
            stringBuffer.append(temp);
        }
        return stringBuffer.toString();
    }
}