MD5加密

原生手写MD5加密方法：

package com.wiimedia.mryl.utils;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/** * * @Title: MD5.java * * @Package: com.wiimedia.mryl.utils * * @Company: WiiMedia * * @Description: 对密码进行加密 * * @author: SongJia * * @date: 2016-1-13 下午4:39:45 */


public final class MD5 {

        /** * Message digest. */
        private static MessageDigest messageDigest;

        /** * Low 8 bits all sets to 1. */
        private static final int LOW_8_BITS_1 = 0xff;

        /** * Append size. */
        private static final int APPEND_SIZE = 16;

        /** * Private default constructor. */

        private MD5() {}

        static {
            try {
                messageDigest = MessageDigest.getInstance("MD5");
            } catch (final NoSuchAlgorithmException e) {
                throw new RuntimeException(e);
            }
        }

        /** * Hashs(MD5) the specified string. * * @param string the specified string * * @return hashed string from the specified string */
        public static String hash(final String string) {

            final char[] charArray = string.toCharArray();
            final byte[] byteArray = new byte[charArray.length];

            for (int i = 0; i < charArray.length; i++) {
                byteArray[i] = (byte) charArray[i];
            }

            final byte[] bytes = messageDigest.digest(byteArray);
            final StringBuffer hexValue = new StringBuffer();

            for (int i = 0; i < bytes.length; i++) {
                final int val = ((int) bytes[i]) & LOW_8_BITS_1;

                if (val < APPEND_SIZE) {
                    hexValue.append("0");
                }
                hexValue.append(Integer.toHexString(val));
            }
            return hexValue.toString();
        }

    }