Java MD5加密

import  java.security.*;  
import  java.security.spec.*;  

class  MD5_test {  
 public   final   static  String MD5(String s) {  
  char  hexDigits[] = {  '0' ,  '1' ,  '2' ,  '3' ,  '4' ,  '5' ,  '6' ,  '7' ,  '8' ,  '9' ,  
    'a' ,  'b' ,  'c' ,  'd' ,  'e' ,  'f'  };  
  try  {  
   byte [] strTemp = s.getBytes();  
   MessageDigest mdTemp = MessageDigest.getInstance("MD5" );  
   mdTemp.update(strTemp);  
   byte [] md = mdTemp.digest();  
   int  j = md.length;  
   char  str[] =  new   char [j *  2 ];  
   int  k =  0 ;  
   for  ( int  i =  0 ; i < j; i++) {  
    byte  byte0 = md[i];  
    str[k++] = hexDigits[byte0 >>> 4  &  0xf ];  
    str[k++] = hexDigits[byte0 & 0xf ];  
   }  
   return   new  String(str);  
  } catch  (Exception e) {  
   return   null ;  
  }  
 }  

 public   static   void  main(String[] args) {  
  // MD5_Test aa = new MD5_Test();   
  System.out.print(MD5_test.MD5("186834546_pp$tv@2012" ));  
 }  
}