public boolean isDomain() {
        return StringUtils.isNotBlank(nacosDomain);
    }
@Test
    void testIsDomain() throws IOException {
        Properties properties = new Properties();
        properties.put(PropertyKeyConst.SERVER_ADDR, "127.0.0.1:8848");
        serverListManager = new ServerListManager(properties);
        assertTrue(serverListManager.isDomain());
        assertEquals("127.0.0.1:8848", serverListManager.getNacosDomain());
    }