java加密算法之MD5篇

Posted 2022-12-13 lwx-apollo

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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