MessageDigest 例子

public static String getMD5Str(String str) {MessageDigest messageDigest = null;try {messageDigest = MessageDigest.getInstance("MD5");messageDigest.reset();messageDigest.update(str.getBytes("UTF-8"));} catch (NoSuchAlgorithmException e) {System.out.println("NoSuchAlgorithmException caught!");System.exit(-1);} catch (UnsupportedEncodingException e) {e.printStackTrace();}byte[] byteArray = messageDigest.digest();StringBuffer md5StrBuff = new StringBuffer();for (int i = 0; i < byteArray.length; i++) {if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i]));elsemd5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));}return md5StrBuff.toString();}