package com.wjz.util;import java.security.MessageDigest;import org.apache.log4j.Logger;/** * MD5安全加密 * @author wjz * */public class MD5Util {        private static Logger logger = Logger.getLogger(MD5Util.class);    private MD5Util(){    }        /**     * MD5安全加密     * @param value 原始密文     * @param count 加密次数     * @return 加密密文     */    public static String encrypt(String value , int count){        String result = null;        try {             MessageDigest md5 = MessageDigest.getInstance("MD5");             //使用指定的字节加密原始字节             md5.update(value.getBytes());             //获得加密之后的字节             byte[] bs = md5.digest();             if(count > 1)                  result = encrypt(byte2String(bs), count-1);             //把密文转换成十六进制的字符串形式             result = byte2String(bs);        } catch (Exception e) {            logger.error(e.getMessage());            e.printStackTrace();        }        return result;    }        private static String byte2String(byte[] bs) {        //String本质上是字符数组        //byte是字节，char是字符，一个字符等于两个字节        char[] hexDigits = {'0','1','2','3','4','5','6','7','8','9', 'A','B','C','D','E','F' };        int i = 0;        char[] resultArry = new char[bs.length*2];        for (byte b : bs) {            //0xf表示16进制的F=15(二进制：00001111);            resultArry[i++] = hexDigits[b >>> 4 & 0xf];            resultArry[i++] = hexDigits[b & 0xf];        }        // 字符数组组合成字符串返回        return new String(resultArry);    }}