public static BigDecimal round(double v, int scale) {
		return round(v, scale, RoundingMode.HALF_UP);
	}
@Test
	public void roundTest() {

		// 四舍
		final String round1 = NumberUtil.roundStr(2.674, 2);
		final String round2 = NumberUtil.roundStr("2.674", 2);
		assertEquals("2.67", round1);
		assertEquals("2.67", round2);

		// 五入
		final String round3 = NumberUtil.roundStr(2.675, 2);
		final String round4 = NumberUtil.roundStr("2.675", 2);
		assertEquals("2.68", round3);
		assertEquals("2.68", round4);

		// 四舍六入五成双
		final String round31 = NumberUtil.roundStr(4.245, 2, RoundingMode.HALF_EVEN);
		final String round41 = NumberUtil.roundStr("4.2451", 2, RoundingMode.HALF_EVEN);
		assertEquals("4.24", round31);
		assertEquals("4.25", round41);

		// 补0
		final String round5 = NumberUtil.roundStr(2.6005, 2);
		final String round6 = NumberUtil.roundStr("2.6005", 2);
		assertEquals("2.60", round5);
		assertEquals("2.60", round6);

		// 补0
		final String round7 = NumberUtil.roundStr(2.600, 2);
		final String round8 = NumberUtil.roundStr("2.600", 2);
		assertEquals("2.60", round7);
		assertEquals("2.60", round8);
	}