public static String getClientIdentify(HttpServletRequest request) {
        String identify = request.getHeader(LONG_PULLING_CLIENT_IDENTIFICATION);
        return StringUtil.isBlank(identify) ? "" : identify;
    }
@Test
    public void notExistClientIdentifyTest() {
        MockHttpServletRequest request = new MockHttpServletRequest();
        String clientIdentify = RequestUtil.getClientIdentify(request);
        Assert.isTrue(Objects.equals(clientIdentify, ""));
    }