Java版MD5加密工具类

package com;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.MessageDigest;

public class MD5Util {

    /**
     * @param args
     *
     *
     */
    static Logger logger = LoggerFactory.getLogger(MD5Util.class);

    private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "A", "B", "C", "D", "E", "F" };

    /**
     * 转换字节数组为16进制字串
     *
     * @param b
     *            字节数组
     * @return 16进制字串
     */
    public static String byteArrayToHexString(byte[] b) {

        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    /**
     * J 转换byte到16进制
     *
     * @param b
     * @return
     */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0) {
            n = 256 + n;
        }
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }


    // MessageDigest 为 JDK 提供的加密类
    public static String MD5Encode(String origin) {

        if (origin == null)
            return null;
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            resultString = byteArrayToHexString(md.digest(resultString
                    .getBytes()));
        } catch (Exception ex) {
            logger.error(MD5EncodeUtil.class + " --MD5加密异常：" + ex);
        }
        return resultString;
    }


    public static void main(String[] args) {
        System.out.println(MD5Encode("1"));
        // String a = null;
        // System.out.println( new String(a) );
    }

}