private static void Md5(String plainText ) { try { MessageDigest md = MessageDigest.getInstance("MD5"); md.update(plainText.getBytes()); byte b[] = md.digest(); int i; StringBuffer buf = new StringBuffer(""); for (int offset = 0; offset < b.length; offset++) { i = b[offset]; if(i<0) i+= 256; if(i<16) buf.append("0"); buf.append(Integer.toHexString(i)); } System.out.println("result: " + buf.toString());//32位的加密 System.out.println("result: " + buf.toString().substring(8,24));//16位的加密 } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } }