public static boolean equals(String a, String b) {
        if (a == null) {
            return b == null;
        }
        return a.equals(b);
    }
@Test
    void testEquals() {
        Assertions.assertTrue(StringUtils.equals("1", "1"));
        Assertions.assertFalse(StringUtils.equals("1", "2"));
        Assertions.assertFalse(StringUtils.equals(null, "1"));
        Assertions.assertFalse(StringUtils.equals("1", null));
        Assertions.assertFalse(StringUtils.equals("", null));
        Assertions.assertFalse(StringUtils.equals(null, ""));
    }