利用Java計算String的MD5

	private final String[] strDigits = { "0", "1", "2", "3", "4", "5", "6",
			"7", "8", "9", "a", "b", "c", "d", "e", "f" };

	private String byteToArrayString(byte bByte) {
		int iRet = bByte;
		if (iRet < 0) {
			iRet += 256;
		}
		int iD1 = iRet / 16;
		int iD2 = iRet % 16;
		return strDigits[iD1] + strDigits[iD2];
	}

	private String byteToString(byte[] bByte) {
		StringBuffer sBuffer = new StringBuffer();
		for (int i = 0; i < bByte.length; i++) {
			sBuffer.append(byteToArrayString(bByte[i]));
		}
		return sBuffer.toString();
	}

	public String GetMD5Code(String strObj) {
		String resultString = null;
		try {
			resultString = new String(strObj);
			MessageDigest md = MessageDigest.getInstance("MD5");
			resultString = byteToString(md.digest(strObj.getBytes()));
		} catch (NoSuchAlgorithmException ex) {
			ex.printStackTrace();
		}
		return resultString;
	}

在mian函數中調用GetMD5Code(str)方法即可。