RestTemplate template = new RestTemplate();

        String appid =  "aa";

        String secret = "bb";

        String tokenUrl = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid="+appid+"&secret="+secret;

        @SuppressWarnings("rawtypes")

        Map map = template.getForObject(tokenUrl, Map.class);

        Object obj1 =  map.get("access_token");

        if(obj1 == null){ // access_token ERROR!

            return "";

        }

        String accessToken = (String) obj1;