J2EE常用工具类——MD5加密

package cn.org.jshuwei.j2ee.util;

import java.security.MessageDigest;

/**
* 
* MD5加密工具类
* 
* @author huwei(jshuwei.org.cn)
* @since 1.4
* 
*/
public class MD5 {
    private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

    private static String byteArrayToHexString(byte[] bytes) {
        StringBuffer sb = new StringBuffer();
        for (byte b : bytes) {
            sb.append(byteToHexString(b));
        }
        return sb.toString();
    }

    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];
    }

    /**
     * 将字符串加密成MD5字符串
     * 
     * @param origin
     *            需要加密的字符串
     * @return 加密后的字符串
     */
    public static String MD5Encode(String origin) {
        String ret = null;
        try {
            ret = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            ret = byteArrayToHexString(md.digest(ret.getBytes()));
        } catch (Exception e) {
        }
        return ret;
    }
}