### Question:
WxCpUserServiceImpl implements WxCpUserService { @Override public String openid2UserId(String openid) throws WxErrorException { String url = "https: JsonObject jsonObject = new JsonObject(); jsonObject.addProperty("openid", openid); String responseContent = this.mainService.post(url, jsonObject.toString()); JsonElement tmpJsonElement = new JsonParser().parse(responseContent); return tmpJsonElement.getAsJsonObject().get("userid").getAsString(); } WxCpUserServiceImpl(WxCpService mainService); @Override void authenticate(String userId); @Override void create(WxCpUser user); @Override void update(WxCpUser user); @Override void delete(String... userIds); @Override WxCpUser getById(String userid); @Override List<WxCpUser> listByDepartment(Integer departId, Boolean fetchChild, Integer status); @Override List<WxCpUser> listSimpleByDepartment(Integer departId, Boolean fetchChild, Integer status); @Override WxCpInviteResult invite(List<String> userIds, List<String> partyIds, List<String> tagIds); @Override Map<String, String> userId2Openid(String userId, Integer agentId); @Override String openid2UserId(String openid);  }### Answer:
@Test public void testOpenid2UserId() throws Exception { String result = this.wxCpService.getUserService().openid2UserId(userId); System.out.println(result); assertNotNull(result); }