public static int indexOf(CharSequence str, char searchChar) {
		return indexOf(str, searchChar, 0);
	}
@Test
	public void indexOfTest2() {
		int index = CharSequenceUtil.indexOf("abc123", '1', 0, 3);
		assertEquals(-1, index);

		index = CharSequenceUtil.indexOf("abc123", 'b', 0, 3);
		assertEquals(1, index);
	}