public static Map<String, String> parseQueryString(String qs) {
        if (isEmpty(qs)) {
            return new HashMap<>();
        }
        return parseKeyValuePair(qs, "\\&");
    }
@Test
    void testParseQueryString() throws Exception {
        assertThat(StringUtils.getQueryStringValue("key1=value1&key2=value2", "key1"), equalTo("value1"));
        assertThat(StringUtils.getQueryStringValue("key1=value1&key2=value2", "key2"), equalTo("value2"));
        assertThat(StringUtils.getQueryStringValue("", "key1"), isEmptyOrNullString());
    }