public static String bankCard(String bankCardNo) {
		if (StrUtil.isBlank(bankCardNo)) {
			return bankCardNo;
		}
		bankCardNo = StrUtil.cleanBlank(bankCardNo);
		if (bankCardNo.length() < 9) {
			return bankCardNo;
		}

		final int length = bankCardNo.length();
		final int endLength = length % 4 == 0 ? 4 : length % 4;
		final int midLength = length - 4 - endLength;

		final StringBuilder buf = new StringBuilder();
		buf.append(bankCardNo, 0, 4);
		for (int i = 0; i < midLength; ++i) {
			if (i % 4 == 0) {
				buf.append(CharUtil.SPACE);
			}
			buf.append('*');
		}
		buf.append(CharUtil.SPACE).append(bankCardNo, length - endLength, length);
		return buf.toString();
	}
@Test
	public void bankCardTest(){
		assertEquals(null, DesensitizedUtil.bankCard(null));
		assertEquals("", DesensitizedUtil.bankCard(""));
		assertEquals("1234 **** **** **** **** 9", DesensitizedUtil.bankCard("1234 2222 3333 4444 6789 9"));
		assertEquals("1234 **** **** **** **** 91", DesensitizedUtil.bankCard("1234 2222 3333 4444 6789 91"));
		assertEquals("1234 **** **** **** 6789", DesensitizedUtil.bankCard("1234 2222 3333 4444 6789"));
		assertEquals("1234 **** **** **** 678", DesensitizedUtil.bankCard("1234 2222 3333 4444 678"));

	}