MD5加密 --Java

public static String getMD5Str(String str) {
		MessageDigest messageDigest = null;
		try {
			messageDigest = MessageDigest.getInstance("MD5");
			messageDigest.reset();

			messageDigest.update(str.getBytes("UTF-8"));
		} catch (Exception e) {
		}

		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]));
			} else {
				md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));
			}
		}

		return md5StrBuff.toString();
	}