一个实现MD5的简洁的java类

一个实现MD5的简洁的java类

作者：未知 来源：未知 加入时间：2005-9-26 人气：2

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由于消息摘要唯一性和不可逆性的特点，所以不失为一种简单的常用的加密手段，比如你可以用md5来加密你的应用中的用户口令。

1. packagetest;
2. importjava.security.MessageDigest;
3. /**
4. *<p>Title:</p>
5. *<p>Description:</p>
6. *<p>Copyright:Copyright(c)2003</p>
7. *<p>Company:</p>
8. *@authorunascribed
9. *@version1.0
10. */
11. 
    
12. publicclassStringUtil{
13. 
    
14. privatefinalstaticString[]hexDigits={
15. "0","1","2","3","4","5","6","7",
16. "8","9","a","b","c","d","e","f"};
17. 
    
18. /**
19. *转换字节数组为16进制字串
20. *@paramb字节数组
21. *@return16进制字串
22. */
23. 
    
24. publicstaticStringbyteArrayToHexString(byte[]b){
25. StringBufferresultSb=newStringBuffer();
26. for(inti=0;i<b.length;i++){
27. resultSb.append(byteToHexString(b[i]));
28. }
29. returnresultSb.toString();
30. }
31. 
    
32. privatestaticStringbyteToHexString(byteb){
33. intn=b;
34. if(n<0)
35. n=256+n;
36. intd1=n/16;
37. intd2=n%16;
38. returnhexDigits[d1]+hexDigits[d2];
39. }
40. 
    
41. publicstaticStringMD5Encode(Stringorigin){
42. StringresultString=null;
43. 
    
44. try{
45. resultString=newString(origin);
46. MessageDigestmd=MessageDigest.getInstance("MD5");
47. resultString=byteArrayToHexString(md.digest(resultString.getBytes()));
48. }
49. catch(Exceptionex){
50. 
    
51. }
52. returnresultString;
53. }
54. 
    
55. publicstaticvoidmain(String[]args){
56. System.err.println(MD5Encode("a"));
57. }
58. }

在RFC1321中，给出了Testsuite用来检验你的实现是否正确：

MD5("")=d41d8cd98f00b204e9800998ecf8427e
MD5("a")=0cc175b9c0f1b6a831c399e269772661
MD5("abc")=900150983cd24fb0d6963f7d28e17f72
MD5("messagedigest")=f96b697d7cb7938d525a2f31aaf161d0
MD5("abcdefghijklmnopqrstuvwxyz")=c3fcd3d76192e4007dfb496cca67e13b