About MD5 Encryption in Java (can be used directly)

This article transferred from: http://www.cnblogs.com/solove/archive/2011/10/18/2216715.html

The upper part is reproduced about the encryption of the string, the latter part is more complete, including string, file, byte array, etc.

2. Package util;
6. Import Java.security.MessageDigest;
10. Public class Encript {
12. //16 binary number-to-character mapping array
14. Private final static string[] Hexdigits = {"0","1","2","3","4","5","6", "7","8","9","A","B","C","D","E","F"};
18. /** Encrypt the inputstring * /
20. public static string MD5 (string inputstr) {
22. return encodeByMD5 (INPUTSTR);
24. }
28. /** 
30. * Verify that the password you entered is correct
32. * @param password Real password (encrypted true password)
34. * @param inputstring Input string
36. * @return Validation result, Boolean type
38. */
40. public Static boolean Authenticatepassword (String password,string inputstring) {
42. if (Password.equals (EncodeByMD5 (inputstring))) {
44. return true;
46. }else{
48. return false;
50. }
52. }
56. /** MD5 Encoding of strings * /
58. private static string EncodeByMD5 (String originstring) {
60. if (originstring!=null) {
62. try {
64. //Create a summary of information with the specified algorithm name
66. MessageDigest MD5 = messagedigest.getinstance ("MD5");
68. //Use the specified byte array to make the last update to the summary and complete the summary calculation
70. byte[] results = md5.digest (Originstring.getbytes ());
72. //The resulting byte array becomes a string return
74. String result = bytearraytohexstring (results);
76. return result;
78. } catch (Exception e) {
80. E.printstacktrace ();
82. }
84. }
86. return null;
88. }
92. /** 
94. * Rotate byte array to hexadecimal string
96. * @param B-byte array
98. * @return Hexadecimal string
100. */
102. private static String bytearraytohexstring (byte[] b) {
104. StringBuffer RESULTSB = new StringBuffer ();
106. For (int i=0;i<b.length;i++) {
108. Resultsb.append (bytetohexstring (b[i));
110. }
112. return resultsb.tostring ();
114. }
118. //Converts a byte into a string of 16 binary form
120. private static String bytetohexstring (byte b) {
122. int n = b;
124. if (n<0)
126. n=256+n;
128. int d1 = n/;
130. int d2 = n%;
132. return HEXDIGITS[D1] + hexdigits[d2];
134. }
136. }
138. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

139. Package com.angsentech.ssm.util;

     Import Java.io.File;
     Import Java.io.FileInputStream;
     Import java.io.IOException;
     Import Java.io.InputStream;
     Import java.io.UnsupportedEncodingException;
     Import Java.security.MessageDigest;
     Import java.security.NoSuchAlgorithmException;

     /**
     * MD5 Cryptographic Processing Tool class
     * @author Administrator
     *
     */

     public class Md5utils {
     /**
     * Default password string combination, used to convert bytes to 16 binary characters, Apache check the correctness of the downloaded file is the default of this combination
     */
     protected static char hexdigits[] = {' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ',
     ' 7 ', ' 8 ', ' 9 ', ' A ', ' B ', ' C ', ' d ', ' e ', ' f '};

     protected static MessageDigest messagedigest = null;
     static {
     try {
     MessageDigest = Messagedigest.getinstance ("MD5");
     } catch (NoSuchAlgorithmException Nsaex) {
     System.err.println (MD5Utils.class.getName ()
     + "Initialization failed, MessageDigest does not support Md5util. ");
     Nsaex.printstacktrace ();
     }
     }

     /**
     * Generate MD5 checksum for string
     *
     * @param s
     * @return
     */
     public static string getmd5string (string s) {
     Return getmd5string (S.getbytes ());
     }

     /**
     * Determine if the MD5 check code of the string matches a known MD5 code
     *
     * @param password
     * The string to validate
     * @param md5pwdstr
     * Known MD5 check code
     * @return
     */
     public static Boolean IsEqualsToMd5 (string password, string md5pwdstr) {
     String s = getmd5string (password);
     Return S.equals (MD5PWDSTR);
     }

     /**
     * MD5 checksum value of generated file
     *
     * @param file
     * @return
     * @throws IOException
     */
     public static String getfilemd5string (file file) throws IOException {
     InputStream fis;
     FIS = new FileInputStream (file);
     byte[] buffer = new byte[1024];
     int numread = 0;
     while ((Numread = fis.read (buffer)) > 0) {
     Messagedigest.update (buffer, 0, numread);
     }
     Fis.close ();
     Return Buffertohex (Messagedigest.digest ());
     }

     /**
     * Generate MD5 checksum value for byte array
     *
     * @param s
     * @return
     */
     public static String getmd5string (byte[] bytes) {
     Messagedigest.update (bytes);
     Return Buffertohex (Messagedigest.digest ());
     }

     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 = hexdigits[(BT & 0xf0) >> 4];//byte-high 4-bit numeric conversion, >>>
     Move to the right of the logic, move the symbol bit to the right, there is no difference between the two symbols found here
     Char C1 = HEXDIGITS[BT & 0xf];//number conversion with low 4 bits in bytes
     Stringbuffer.append (C0);
     Stringbuffer.append (C1);
     }
     
     /**
     * Encrypt the source string to a byte array using MD5
     * @param source
     * @return
     */
     public static byte[] Encode2bytes (String source) {
     byte[] result = NULL;
     try {
     MessageDigest MD = messagedigest.getinstance ("MD5");
     Md.reset ();
     Md.update (Source.getbytes ("UTF-8"));
     result = Md.digest ();
     } catch (NoSuchAlgorithmException e) {
     E.printstacktrace ();
     } catch (Unsupportedencodingexception e) {
     E.printstacktrace ();
     }

     return result;
     }

     /**
     * Use MD5 to encrypt the source string to 32-bit 16 binary number
     * @param source
     * @return
     */
     public static string Encode2hex (string source) {
     byte[] data = encode2bytes (source);
     StringBuffer hexstring = new StringBuffer ();
     for (int i = 0; i < data.length; i++) {
     String hex = integer.tohexstring (0xFF & Data[i]);

     if (hex.length () = = 1) {
     Hexstring.append (' 0 ');
     }

     Hexstring.append (hex);
     }

     return hexstring.tostring ();
     }

     /**
     * Verify string matches
     * @param unknown string to be validated
     * @param okhex using MD5 encrypted 16 binary string
     * @return Match returns True, mismatch returns false
     */
     public static Boolean validate (string unknown, string okhex) {
     Return Okhex.equals (Encode2hex (unknown));
     }
     }

About MD5 Encryption in Java (can be used directly)