import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

/**

 * md5 32位小写加密源码

 *

 * @author 华

 *

 */

public class MD5 {

    /**

     * 全局数组

     */

    private final static String[] strDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",

            "e", "f" };

    public MD5() {

    }

    /**

     * 返回形式为数字和字符串

     *

     * @param bByte

     * @return

     */

    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

     *

     * @param bByte

     * @return

     */

    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();

    }

    /**

     * 将给定的字符串经过md5加密后返回

     *

     * @param strObj

     * @return

     */

    public static String getMD5Code(String str) {

        String resultString = null;

        try {

            // 将给定字符串追加一个静态字符串，以提高复杂度

            resultString = new String(str);

            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(resultString.getBytes()));

        } catch (NoSuchAlgorithmException ex) {

            ex.printStackTrace();

        }

        return resultString;

    }

}