@Test
    public void testReplace() throws Exception {
        assertEquals("1", "1bc45", StringUtil.replace("12345", "23", "bc"));
        assertEquals("2", "1234ef", StringUtil.replace("12345", "5", "ef"));
        assertEquals("3", "ab2345", StringUtil.replace("12345", "1", "ab"));
        assertEquals("4", "a234a", StringUtil.replace("12341", "1", "a"));
        assertEquals("5", "ab234abab234ab", StringUtil.replace("1234112341", "1", "ab"));