MD5生成消息摘要
public class MD5Util { private static final String MD5 = "MD5"; private static final int THIRTY_TWO = 32; private static final int SHIFT = 4; private static final byte BYTE_F = 0xf; private static final char[] hexChars = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; public static String genMD5(String str, String encoding) throws NoSuchAlgorithmException, UnsupportedEncodingException { MessageDigest md = MessageDigest.getInstance(MD5); md.update(str.getBytes(encoding)); byte[] digests = md.digest(); char[] chs = new char[THIRTY_TWO]; int p = 0; for (int i = 0; i < digests.length; i++) { byte digest = digests[i]; chs[p++] = hexChars[digest >>> SHIFT & BYTE_F]; chs[p++] = hexChars[digest & BYTE_F]; } return new String(chs); }}