MD5加密

 1 //MD5加密，32位  
 2     public static String MD5(String str)  
 3     {  
 4         MessageDigest md5 = null;  
 5         try  
 6         {  
 7             md5 = MessageDigest.getInstance("MD5");  
 8         }catch(Exception e)  
 9         {  
10             e.printStackTrace();  
11             return "";  
12         }  
13           
14         char[] charArray = str.toCharArray();  
15         byte[] byteArray = new byte[charArray.length];  
16           
17         for(int i = 0; i < charArray.length; i++)  
18         {  
19             byteArray[i] = (byte)charArray[i];  
20         }  
21         byte[] md5Bytes = md5.digest(byteArray);  
22           
23         StringBuffer hexValue = new StringBuffer();  
24         for( int i = 0; i < md5Bytes.length; i++)  
25         {  
26             int val = ((int)md5Bytes[i])&0xff;  
27             if(val < 16)  
28             {  
29                 hexValue.append("0");  
30             }  
31             hexValue.append(Integer.toHexString(val));  
32         }  
33         return hexValue.toString();  
34     }  
35       
36     // 可逆的加密算法  
37     public static String encryptmd5(String str) {  
38         char[] a = str.toCharArray();  
39         for (int i = 0; i < a.length; i++)   
40         {  
41                 a[i] = (char) (a[i] ^ ‘l‘);  
42         }  
43         String s = new String(a);  
44         return s;  
45     }