package util;

 import java.security.MessageDigest;

 import java.security.NoSuchAlgorithmException;

 import java.util.Random;

 import org.apache.commons.codec.binary.Hex;

 public class MD5Util {

     /**

      * 普通MD5

      *

      * @author daniel

      * @time 2016-6-11 下午8:00:28

      * @param inStr

      * @return

      */

     public static String MD5(String input) {

         MessageDigest md5 = null;

         try {

             md5 = MessageDigest.getInstance("MD5");

         } catch (NoSuchAlgorithmException e) {

             return "check jdk";

         } catch (Exception e) {

             e.printStackTrace();

             return "";

         }

         char[] charArray = input.toCharArray();

         byte[] byteArray = new byte[charArray.length];

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

             byteArray[i] = (byte) charArray[i];

         byte[] md5Bytes = md5.digest(byteArray);

         StringBuffer hexValue = new StringBuffer();

         for (int i = 0; i < md5Bytes.length; i++) {

             int val = ((int) md5Bytes[i]) & 0xff;

             if (val < 16)

                 hexValue.append("0");

             hexValue.append(Integer.toHexString(val));

         }

         return hexValue.toString();

     }

     /**

      * 加盐MD5

      *

      * @author daniel

      * @time 2016-6-11 下午8:45:04

      * @param password

      * @return

      */

     public static String generate(String password) {

         Random r = new Random();

         StringBuilder sb = new StringBuilder(16);

         sb.append(r.nextInt(99999999)).append(r.nextInt(99999999));

         int len = sb.length();

         if (len < 16) {

             for (int i = 0; i < 16 - len; i++) {

                 sb.append("0");

             }

         }

         String salt = sb.toString();

         password = md5Hex(password + salt);

         char[] cs = new char[48];

         for (int i = 0; i < 48; i += 3) {

             cs[i] = password.charAt(i / 3 * 2);

             char c = salt.charAt(i / 3);

             cs[i + 1] = c;

             cs[i + 2] = password.charAt(i / 3 * 2 + 1);

         }

         return new String(cs);

     }

     /**

      * 校验加盐后是否和原文一致

      *

      * @author daniel

      * @time 2016-6-11 下午8:45:39

      * @param password

      * @param md5

      * @return

      */

     public static boolean verify(String password, String md5) {

         char[] cs1 = new char[32];

         char[] cs2 = new char[16];

         for (int i = 0; i < 48; i += 3) {

             cs1[i / 3 * 2] = md5.charAt(i);

             cs1[i / 3 * 2 + 1] = md5.charAt(i + 2);

             cs2[i / 3] = md5.charAt(i + 1);

         }

         String salt = new String(cs2);

         return md5Hex(password + salt).equals(new String(cs1));

     }

     /**

      * 获取十六进制字符串形式的MD5摘要

      */

     private static String md5Hex(String src) {

         try {

             MessageDigest md5 = MessageDigest.getInstance("MD5");

             byte[] bs = md5.digest(src.getBytes());

             return new String(new Hex().encode(bs));

         } catch (Exception e) {

             return null;

         }

     }

     public static void main(String[] args) {

         String text = "zxcvbnm";

         System.out.println("原始的：" + MD5(text));

         System.out.println("加盐后：" + generate(text));

         System.out.println("比较后：" + verify("zxcvbnm0", generate(text)));

         //tempSalt 某一次加盐后的值

         String[] tempSalt = {

                 "66b120750d59952c8755b66eb3f59242e95ba51d2648bb09",

                 "e58361192f98839e10c6b64ce8b688301b4e722a8f672505",

                 "52817d504304212a46f58f81b9bd42a57f2468fc73b79b61"

         };

         for (String temp : tempSalt) {

             System.out.println("是否是同一字符串:" + verify("zxcvbnm", temp));

         }

     }

 }