MAC是消息摘要算法的第三种实现方式，另外两种方式分别为：MD2\4\5、SHA。

MAC的jdk实现：1、默认密钥方式

private static void MAC_JDK(){        try {            KeyGenerator keyGenerator = KeyGenerator.getInstance("HmacMD5");//初始化KeyGenerator            SecretKey secretKey = keyGenerator.generateKey();//产生密钥            byte[] key = secretKey.getEncoded();//获得默认密钥                        SecretKey restorSecretKey = new SecretKeySpec(key, "HmacMD5");//还原密钥            Mac mac = Mac.getInstance(restorSecretKey.getAlgorithm());//示例化MAC            mac.init(restorSecretKey);//初始化MAC            byte[] hmacMD5Bytes = mac.doFinal(src.getBytes());//执行摘要            System.out.println("hmacMD5Byte : "+Hex.encodeHexString(hmacMD5Bytes));        } catch (Exception e) {            e.printStackTrace();        }        }

2、动态密钥方式：

private static void MAC_JDK_dongtai(){        try {            byte[] key = Hex.decodeHex(new char[]{'a','a','a','a','a','a','a','a','a','a'});//动态获得密钥                        SecretKey restorSecretKey = new SecretKeySpec(key, "HmacMD5");//还原密钥            Mac mac = Mac.getInstance(restorSecretKey.getAlgorithm());//示例化MAC            mac.init(restorSecretKey);//初始化MAC            byte[] hmacMD5Bytes = mac.doFinal(src.getBytes());//执行摘要            System.out.println("hmacMD5Byte : "+Hex.encodeHexString(hmacMD5Bytes));        } catch (Exception e) {            e.printStackTrace();        }        }

MAC的BC实现：

private static void MAC_BC(){        HMac hmac = new HMac(new MD5Digest());        hmac.init(new KeyParameter(org.bouncycastle.util.encoders.Hex.decode("aaaaaaaaaa")));        hmac.update(src.getBytes(), 0, src.getBytes().length);                byte[] mac_BC_Byte = new byte[hmac.getMacSize()];//执行摘要        hmac.doFinal(mac_BC_Byte, 0);        System.out.println("mac_BC_Byte : "+Hex.encodeHexString(mac_BC_Byte));    }

　　到今天JAVA中的Base64、对称加密、消息摘要加密的实现总结就完工了，如果哪位对此感兴趣，还望多多交流。（1453296946@qq.com）