微信获得access-token

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;