MD5 加密 java代码实现

 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"));
     }
 }