public static boolean isEquals(String s1, String s2) {
        if (s1 == null && s2 == null) {
            return true;
        }
        if (s1 == null || s2 == null) {
            return false;
        }
        return s1.equals(s2);
    }
@Test
    void testIsEquals() throws Exception {
        assertTrue(StringUtils.isEquals(null, null));
        assertFalse(StringUtils.isEquals(null, ""));
        assertTrue(StringUtils.isEquals("abc", "abc"));
        assertFalse(StringUtils.isEquals("abc", "ABC"));
    }