package com.company.fjf;

 import java.security.MessageDigest;

 import java.security.NoSuchAlgorithmException;

 public class MD5Test {

     private final static String[] strDigits = { "0", "1", "2", "3", "4", "5",

             "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

     public MD5Test() {

     }

     // return Hexadecimal

     private static String byteToArrayString(byte bByte) {

         int iRet = bByte;

         if (iRet < 0) {

             iRet += 256;

         }

         int iD1 = iRet / 16;

         int iD2 = iRet % 16;

         return strDigits[iD1] + strDigits[iD2];

     }

     // 转换字节数组为16进制字串

     private static String byteToString(byte[] bByte) {

         StringBuffer sBuffer = new StringBuffer();

         for (int i = 0; i < bByte.length; i++) {

             sBuffer.append(byteToArrayString(bByte[i]));

         }

         return sBuffer.toString().toUpperCase();

     }

     public static String GetMD5Code(String strObj) {

         String resultString = null;

         try {

             resultString = new String(strObj);

             MessageDigest md = MessageDigest.getInstance("MD5");

             // md.digest() 该函数返回值为存放哈希值结果的byte数组

             resultString = byteToString(md.digest(strObj.getBytes()));

         } catch (NoSuchAlgorithmException ex) {

             ex.printStackTrace();

         }

         return resultString;

     }

     public static void main(String[] args) {

         System.out.println(MD5Test.GetMD5Code("aaaa"));

     }

 }