16位MD5加密JAVA版

import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; class MD5Security { private final static char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' }; private static String bytesToHex(byte[] bytes) { StringBuffer sb = new StringBuffer(); int t; for (int i = 0; i < 16; i++) { t = bytes[i]; if (t < 0) t += 256; sb.append(hexDigits[(t >>> 4)]); sb.append(hexDigits[(t % 16)]); } return sb.toString(); } public static String md5(String input) throws Exception { return code(input, 32); } public static String code(String input, int bit) throws Exception { try { MessageDigest md = MessageDigest.getInstance(System.getProperty( "MD5.algorithm", "MD5")); if (bit == 16) return bytesToHex(md.digest(input.getBytes("utf-8"))) .substring(8, 24); return bytesToHex(md.digest(input.getBytes("utf-8"))); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); throw new Exception("Could not found MD5 algorithm.", e); } } public static String md5_3(String b) throws Exception{ MessageDigest md = MessageDigest.getInstance(System.getProperty( "MD5.algorithm", "MD5")); byte[] a = md.digest(b.getBytes()); a = md.digest(a); a = md.digest(a); return bytesToHex(a); } }