A concise Java class that implements MD5

Because of the uniqueness and irreversibility of message digest, it is a simple and commonly used encryption method, for example, you can use MD5 to encrypt the user password in your application.

2. Package test;
4. Import Java.security.MessageDigest;
6. /**
8. * <p>title: </p>
10. * <p>description: </p>
12. * <p>copyright:copyright (c) 2003</p>
14. * <p>company: </p>
16. * @author unascribed
18. * @version 1.0
20. */
24. public class Stringutil {
28. Private final static string[] Hexdigits = {
30. "0", "1", "2", "3", "4", "5", "6", "7",
32. "8", "9", "a", "B", "C", "D", "E", "F"};
36. /**
38. * Convert byte array to 16 string
40. * @param B-byte array
42. * @return 16 string
44. */
48. public static String bytearraytohexstring (byte[] b) {
50. StringBuffer RESULTSB = new StringBuffer ();
52. for (int i = 0; i < b.length; i++) {
54. Resultsb.append (bytetohexstring (b[i));
56. }
58. return resultsb.tostring ();
60. }
64. private static String bytetohexstring (Byte b) {
66. int n = b;
68. if (n < 0)
70. n = 256 + N;
72. int D1 = N/16;
74. int d2 = n% 16;
76. return HEXDIGITS[D1] + HEXDIGITS[D2];
78. }
82. public static string Md5encode (string origin) {
84. String resultstring = null;
88. try {
90. Resultstring=new String (origin);
92. MessageDigest MD = messagedigest.getinstance ("MD5");
94. Resultstring=bytearraytohexstring (Md.digest (Resultstring.getbytes ()));
96. }
98. catch (Exception ex) {
102. }
104. return resultstring;
106. }
110. public static void Main (string[] args) {
112. System.err.println (Md5encode ("a"));
114. }
116. }

In RFC 1321, the test suite is given to verify that your implementation is correct:

MD5 ("") = d41d8cd98f00b204e9800998ecf8427e
MD5 ("a") = 0cc175b9c0f1b6a831c399e269772661
MD5 ("abc") = 900150983cd24fb0d6963f7d28e17f72
MD5 ("message digest") = F96b697d7cb7938d525a2f31aaf161d0
MD5 ("abcdefghijklmnopqrstuvwxyz") = c3fcd3d76192e4007dfb496cca67e13b