java加密算法之MD5篇

字符串转MD5

 public static String toMD5(String str) {
    MessageDigest messagedigest;
    try {
        messagedigest = MessageDigest.getInstance("MD5");
        messagedigest.update(str.getBytes("UTF-8"));
        return bufferToHex(messagedigest.digest()).toUpperCase();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

对象转MD5

public static String toMD5(Object obj) {
    String resultString = null;
    try {
        MessageDigest md = MessageDigest.getInstance("MD5");
        resultString = byteToString(md.digest(JsonUtils.toJson(obj).getBytes())).toUpperCase();
    } catch (NoSuchAlgorithmException ex) {
        ex.printStackTrace();
    }
    return resultString;
}

测试

public static void main(String[] args) {
    String str = toMD5("test");
    System.out.println("There is string md5 value :" + str);
    Map<String,Object> obj = new HashMap<>();
    obj.put("param1","param1");
    String object = toMD5(obj);
    System.out.println("There is object md5 value :" + object);
}

测试结果

全代码

public class MD5Utils {
    private static char md5Chars[] =
            {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd',
                    'e', 'f'};

    private final static String[] STR_DIGITS = {"0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};


    private static String bufferToHex(byte bytes[]) {
        return bufferToHex(bytes, 0, bytes.length);
    }

    private static String bufferToHex(byte bytes[], int m, int n) {
        StringBuffer stringbuffer = new StringBuffer(2 * n);
        int k = m + n;
        for (int l = m; l < k; l++) {
            appendHexPair(bytes[l], stringbuffer);
        }
        return stringbuffer.toString();
    }

    private static void appendHexPair(byte bt, StringBuffer stringbuffer) {
        char c0 = md5Chars[(bt & 0xf0) >> 4];
        char c1 = md5Chars[bt & 0xf];
        stringbuffer.append(c0);
        stringbuffer.append(c1);
    }

    public static String toMD5(String str) {
        MessageDigest messagedigest;
        try {
            messagedigest = MessageDigest.getInstance("MD5");
            messagedigest.update(str.getBytes("UTF-8"));
            return bufferToHex(messagedigest.digest()).toUpperCase();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public static String toMD5(Object obj) {
        String resultString = null;
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            resultString = byteToString(md.digest(JsonUtils.toJson(obj).getBytes())).toUpperCase();
        } catch (NoSuchAlgorithmException ex) {
            ex.printStackTrace();
        }
        return resultString;
    }

    private static String byteToArrayString(byte bByte) {
        int iRet = bByte;
        if (iRet < 0) {
            iRet += 256;
        }
        int iD1 = iRet / 16;
        int iD2 = iRet % 16;
        return STR_DIGITS[iD1] + STR_DIGITS[iD2];
    }

    private static String byteToString(byte[] bByte) {
        StringBuffer sBuffer = new StringBuffer();
        for (int i = 0; i < bByte.length; i++) {
            sBuffer.append(byteToArrayString(bByte[i]));
        }
        return sBuffer.toString();
    }

    public static void main(String[] args) {
        String str = toMD5("test");
        System.out.println("There is string md5 value :" + str);
        Map<String,Object> obj = new HashMap<>();
        obj.put("param1","param1");
        String object = toMD5(obj);
        System.out.println("There is object md5 value :" + object);
    }
}

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