常用MD5工具类

import java.io.UnsupportedEncodingException;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;public class Md5Encrypt {    private static final char[] DIGITS = { '0', '1', '2', '3', '4', '5', '6',            '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };    public static String md5(String text) {        MessageDigest msgDigest = null;        try {            msgDigest = MessageDigest.getInstance("MD5");        } catch (NoSuchAlgorithmException e) {            throw new IllegalStateException(                    "System doesn't support MD5 algorithm.");        }        try {            msgDigest.update(text.getBytes("GBK"));        } catch (UnsupportedEncodingException e) {            throw new IllegalStateException(                    "System doesn't support your  EncodingException.");        }        byte[] bytes = msgDigest.digest();        String md5Str = new String(encodeHex(bytes));        return md5Str;    }    public static char[] encodeHex(byte[] data) {        int l = data.length;        char[] out = new char[l << 1];        int i = 0;        for (int j = 0; i < l; i++) {            out[(j++)] = DIGITS[((0xF0 & data[i]) >>> 4)];            out[(j++)] = DIGITS[(0xF & data[i])];        }        return out;    }}