Java实现MD5加密

package com.lichen.test;

import java.security.MessageDigest; 
public class Test_MD5{ 
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(); 
   //使用MD5创建MessageDigest对象 
   MessageDigest mdTemp = MessageDigest.getInstance("MD5"); //MD5也可以换成SHA-1
   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 b = md[i]; 
    //System.out.println((int)b); 
    //将没个数(int)b进行双字节加密 
    str[k++] = hexDigits[b >> 4 & 0xf]; 
    str[k++] = hexDigits[b & 0xf]; 
   } 
   return new String(str); 
  } catch (Exception e) {return null;} 
  } 
  //测试 
public static void main(String[] args) { 
  System.out.println("MD5加密后：\n"+Test_MD5.MD5("嚄")); 
} 
}